1.- Conductance decay of a surface hydrogen tunneling junction fabricated along a Si(001)-(2X1)-H atomic wire PHYSICAL REVIEW B 81, 195316 (2010)

2.- Quantum design rules for single molecule logic gates PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 13, 14404 (2011)

3.-Single OR molecule and OR atomic circuit logic gates interconnected on a Si(100)H surface J. PHYS. COND. MAT., 23, 125303 (2011)

4.- Classical Boolean Logic gates with Quantum System J. PHYS. A, 44, 155302 (2011)

5.- A time-dependant approach to electronic transmission in model 5olecular junctions J. PHYS. CHEM. B, 115, 5582 (2011)

6.-Synthesis of fluoranthenes by hydroarylation of alkynes catalyzed by gold (I) or gallium trichloride Beilstein  JOURNAL ORGANIC CHEMISTRY 7, 1520–1525 (2011)

7.- Atomic- and molecular-scale devices and systems for single-molecule electronics PHYS. STATUS SOLIDI A, doi: 10.1002/pssa.201127623 (2012)

8.- The different designs of molecule logic gates ADV. MATERIALS, 2011, XX, 1–6

9.- Methylterrylene isomers TETRAHEDRON 68, 9371-9375 (2012)

10.- Gold for the Generation and Control of Fluxional Barbaralyl Cations ANGEW.CHEM.INT.Ed.,51,1–5 (2012)

11.- Energetics and stability of dangling-bond silicon wires on H passivated Si(100) J. PHYS. COND. MAT 24, 445005 (2012)

12.- Dangling bond logic gates on the Si(100)-(2x1)-H surface J. PHYS. COND. MAT., 24, 095011 (2012)

13.-Surface-State Engineering for Interconnects on H Passivated Si(100) NanoLett., 13, 1192−1195 (2013)

14.-Construction of atomic-scale logic gates on a surface of hydrogen passivated germanium Microelectronic Engineering 109 (2013) 262–265

15.-A Controlled Quantum SWAP Logic Gate in a 4-center Metal Complex Architecture and Design of Molecule Logic Gates and Atom Circuits, Springer Series Advances in Atom and Single Molecule Machines: ISBN: 978-3-642-33136-7 (2013) pages 237-247.

16.-Binary Full Adder in a Single Quantum System Architecture and Design of Molecule Logic Gates and Atom Circuits, Springer Series Advances in Atom and Single Molecule Machines: ISBN: 978-3-642-33136-7 (2013) pages 221-234.

17.-Classical Logic in a Single Molecule Architecture and Design of Molecule Logic Gates and Atom Circuits, Springer Series Advances in Atom and Single Molecule Machines: ISBN: 978-3-642-33136-7 (2013) pages 109-121.

18.-Dangling-Bond Wire Circuits on a Si(001)-(2x1):H Surface with Their Contacting Nanopads Architecture and Design of Molecule Logic Gates and Atom Circuits, Springer Series Advances in Atom and Single Molecule Machines: ISBN: 978-3-642-33136-7 (2013) pages 163-174.

19.-Dangling-Bond Logic: Designing Boolean Logic Gates on a Si(001)-(2x1):H Surface Architecture and Design of Molecule Logic Gates and Atom Circuits, Springer Series Advances in Atom and Single Molecule Machines: ISBN: 978-3-642-33136-7 (2013), pages 149-174.

20.-First-Principles Simulations of Electronic Transport in Dangling-Bond Wires Architecture and Design of Molecule Logic Gates and Atom Circuits, Springer Series Advances in Atom and Single Molecule Machines: ISBN: 978-3-642-33136-7 (2013) pages 137-148

21.-Theory of Inelastic Transport Through Atomic SurfaceWires Architecture and Design of Molecule Logic Gates and Atom Circuits, Springer Series Advances in Atom and Single Molecule Machines: ISBN: 978-3-642-33136-7 (2013), pages 175-185.

22.-Electronic Transmission Through a Single Impurity in a Multi-configuration Scattering Matrix Approach Proceedings of the 3rd AtMol International Workshop, Berlin 24-25 September 2012, “Imaging and Manipulating Molecular Orbitals” Advances in Atom and Single Molecule Machines - Series Editor: Christian Joachim, Springer, ISBN: 978-3-642-38808-8 (2013) pages 137-157.

23.-High Voltage STM Imaging of Single Copper Phthalocyanine Architecture and Design of Molecule Logic Gates and Atom Circuits, Springer Series Advances in Atom and Single Molecule Machines: ISBN: 978-3-642-38808-8 (2013), pages 15-26.

24.-Mapping the Electronic Resonances of Single Molecule STM Tunnel Junctions Architecture and Design of Molecule Logic Gates and Atom Circuits, Springer Series Advances in Atom and Single Molecule Machines: ISBN: 978-3-642-38808-8 (2013), pages 57-67.

25.-Simulations of Constant Current STM Images of Open-Shell Systems Proceedings of the 3rd AtMol International Workshop, Berlin 24-25 September 2012, “Imaging and Manipulating Molecular Orbitals” Advances in Atom and Single Molecule Machines - Series Editor: Christian Joachim, Springer, ISBN: 978-3-642-38808-8 (2013) pages 117-136.

26.-Observations of Individual Cu-Phthalocyanine Molecules Deposited on Nano-Tips in the Field Emission Microscope Architecture and Design of Molecule Logic Gates and Atom Circuits, Springer Series Advances in Atom and Single Molecule Machines: ISBN: 978-3-642-38808-8 (2013), pages 3-13.

27.-Vibrational transition rule during a through-bond electron transfer Process CHEMICAL PHYSICS LETTERS 567 ; 1–5 (2013)

28.-Thermally and Vibrationally Induced Tautomerization of Single Porphycene Molecules on a Cu(110) Surface PRL 111, 246101 (2013)

29.-Manipulation and Spectroscopyof Individual Phthalocyanine Molecules on InAs(111)A with a Low-Temperature Scanning Tunneling Microscope Proceedings of the 3rd AtMol International Workshop, Berlin 24-25 September 2012, “Imaging and Manipulating Molecular Orbitals” Advances in Atom and Single Molecule Machines - Series Editor: Christian Joachim, Springer, ISBN: 978-3-642-38808-8 (2013) pages 69-79.

30.-Quantifying the atomic-level mechanics of single long physisorbed molecular chains PNAS March 18, (2014) vol. 111 no. 11 3968–3972

31.-Gold(I) Carbenes by Retro-Buchner Reaction: Generation and Fate J. Am. Chem. Soc. (2014), 136, 801−809

32.-Spin transport in dangling-bond wires on doped H-passivated Si(100) IOP Publishing Nanotechnology 25 (2014) 465703 (6pp)

Conductance decay of a surface hydrogen tunneling junction fabricated along a Si(001)-(2X1)-H atomic wire

PHYSICAL REVIEW B 81, 195316 (2010)

Authors
Hiroyo Kawai (1), Yong Kiat Yeo (1,2), Mark Saeys (2,*), and Christian Joachim (1,3, †)
1 Institute of Materials Research and Engineering, 3 Research Link, Singapore 117602, Singapore
2 Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117576, Singapore
3 Centre d’Elaboration des Materiaux et d’Etudes Structurales (CEMES), CNRS, 29 rue J.Marvig, 31055 Toulouse Cedex, France
* chesm@nus.edu.sg
† joachim@cemes.fr

Abstract
On a Si(001)-(2X1)-H substrate, electrons tunneling through hydrogen atomic junctions fabricated between two surface dangling-bond (DB) wires are theoretically investigated using the elastic-scattering quantum-chemistry method. The surface states introduced in the Si band gap by removing H atoms from a Si(001)-(2X1)-H surface were calculated and also analyze dusing a simple tight-binding model. The two-channel surface conductance of a DB wire results from a combination of through-space and through-lattice electronic couplings between DB states. The conductance of the DB wire-H-junction-DB wire structure decreases exponentially with the length of H junction with an inverse decay rate ranging from 0.20 to 0.23Å−1, depending on the energy. When the DB wire-H-junction-DB wire structure is contacted by Au nanoelectrodes, the transmission resonances corresponding to the DB wire states split, demonstrating a coupling of the DB wires through short surface hydrogen atomic junctions. This splitting decreases with the length of H junction between the DB wires with an inverse decay length ranging from 0.22 to 0.44Å−1, indicating tha tsuch an atomic scale surface tunneling junction is not a very good insulator.


Quantum design rules for single molecule logic gates

PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 13, 14404 (2011)

Authors
N. Renaud (1), M. Hliwa (2) and C. Joachim (2)
(1) Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA
(2) Nanoscience Group and MANA Satellite CEMES/CNRS, 29 rue J Marvig, BP 94347, 31055 Toulouse Cedex, France

Abstract
Recent publications have demonstrated how to implement a NOR logic gate with a single molecule using its interaction with two surface atoms as logical inputs [Ref: W. Soe et al ACS Nano ]. We demonstrate here how this NOR logic gate belongs to the general family of quantum logic gates where the Boolean truth table results from a full control of the quantum trajectory of the electron transfer process through the molecule by very local and classical inputs practiced on the molecule. A new molecule OR gate is proposed for the logical inputs to be also single metal atoms, one per logical input.

Single OR molecule and OR atomic circuit logic gates interconnected on a Si(100)H surface

J. PHYS. COND. MAT., 23, 125303 (2011)

Authors
F. Ample (1), I. Duchemin (2), M. Hliwa (2,3)and C. Joachim (1,2)
(1) Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (ASTAR), 3 Research Link, Singapore 117602, Singapore
(2) Nanosciences Group & MANA Satellite, CEMES-CNRS, 29 rue Jeanne Marvig, F-31055 Toulouse, France
(3) Faculté des Sciences Ben M'Sik, Université Hassan II-Mohammédia, Sidi Othman, Casablanca, BP 7955, Morocco

Abstract
Electron transport calculations were carried out for three terminal OR logic gates constructed either with a single molecule or with a surface dangling bond circuit interconnected on a Si(100)H surface. The corresponding multi-electrode multi-channel scattering matrix (where the central three terminal junction OR gate is the scattering center) was calculated, taking into account the electronic structure of the supporting Si(100)H surface, the metallic interconnection nano-pads, the surface atomic wires and the molecule. Well interconnected, an optimized OR molecule can only run at a maximum of 10 nA output current intensity for a 0.5 V bias voltage. For the same voltage and with no molecule in the circuit, the output current of an OR surface atomic scale circuit can reach 4 µA.

Classical Boolean Logic gates with Quantum System

J. PHYS. A, 44, 155302 (2011)

Authors
N. Renaud (2) and C. Joachim (1)
(1)Nanoscience Group and MANA Satellite CEMES/CNRS, 29 rue J Marvig, BP 94347, 31055 Toulouse Cedex, France
(2)Present address: Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA n-renaud@northwestern.edu

Abstract
An analytical method is proposed to implement any classical Boolean function in a small quantum system by taking the advantage of its electronic transport properties. The logical input, α = {α1, ..., αN}, is used to control well-identified parameters of the Hamiltonian of the system noted \mathcal {H}_0(\boldsymbol{\alpha }). The logical output is encoded in the tunneling current intensity passing through the quantum system when connected to conducting electrodes. It is demonstrated how to implement the six symmetric two-input/one-output Boolean functions in a quantum system. This system can be switched from one logic function to another by changing its structural parameters. The stability of the logic gates is discussed, perturbing the Hamiltonian with noise sources and studying the effect of decoherence.

A time-dependant approach to electronic transmission in model molecular junctions

J. PHYS. CHEM. B, 115, 5582 (2011)

Authors
N. Renaud†, M. Ratner† and C. Joachim‡
† Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
‡ Nanoscience Group & MANA Sattelite CEMES/CNRS, 29 rue J. Marvig, BP 4347, 31055 Toulouse Cedex, France

Abstract
We present a simple method to compute the transmission coefficient of a quantum system embedded between two conducting electrodes. Starting from the solution of the time-dependent Schrodinger equation, we demonstrate the relationship between the temporal evolution of the state vector, |ψ(t), initially localized on one electrode and the electronic transmission coefficient, T(E). We particularly emphasize the role of the oscillation frequency and the decay rate of |ψ(t) in the line shape of T(E). This method is applied to the well-known problems of the single impurity, two-site systems and the benzene ring, where it agrees with well-accepted time-independent methods and gives new physical insight to the resonance and interference patterns widely observed in molecular junctions.

Synthesis of fluoranthenes by hydroarylation of alkynes catalyzed by gold (I) or gallium trichloride

Beilstein  JOURNAL ORGANIC CHEMISTRY 7, 1520–1525 (2011)

Authors

Sergio Pascual(1), Christophe Bour(1), Paula de Mendoza(1) and Antonio M. Echavarren(*1,2)
(1) Institute of Chemical Research of Catalonia (ICIQ)
Departament de Química Analítica i Química Orgànica, Universitat Rovira i Virgili,
* Antonio M. Echavarren- aechavarren@iciq.es

Abstract
Electrophilic gold (I) catalyst 6 competes with GaCl3 as the catalyst of choice in the synthesis of fluoranthenes by intramolecular hydroarylation of alkynes. The potential of this catalyst for the preparation of polyarenes is illustrated by a synthesis of two functionalized decacyclenes in a one-pot transformation in which three C–C bonds are formed with high efficiency. 

        
Atomic- and molecular-scale devices and systems for single-molecule electronics

PHYS. STATUS SOLIDI A, doi: 10.1002/pssa.201127623 (2012)

Authors
J. S. Prauzner-Bechcicki*, S. Godlewski, M. Szymonski
* Faculty of Physics, Astronomy, and Applied Computer Science, Center for Nanometer-Scale Science and Advanced Materials, NANOSAM, Jagiellonian University, Reymonta 4, 30-059 Krakow, PolandEmail: Jakub S. Prauzner-Bechcicki (jakub.prauzner-bechcicki@uj.edu.pl)
*Phone: +48-126-635540, Fax: +48-126-337086

Abstract
Present-day electronic technology, based to a large extent on silicon fabricated devices, is surely approaching size limitations arising from quantum effects. The effort to achieve rapid development of electronic devices requires implementation of entirely new ideas that will allow existing technological constraints to be overcome. Among a wide range of concepts, utilization of single organic molecules, acting as active blocks performing logic operations, appears as one of the most appealing and is based on the state-of-the-art use of modern nanotechnology. In this short review, we offer a selection of recent experiments addressing milestones of single-molecule computing devices technology. Along with discussion of the latest achievements in atomic- and molecular-scale technologies, we discuss their future perspectives, challenges, and still unsolved issues standing in the way of practical implementation of single-molecule devices.

The different designs of molecule logic gates

ADV. MATERIALS, 2011, XX, 1–6

Authors
C. Joachim (1), N. Renaud (1,2)and M. Hliwa (1)
(1) CEMES & MANA Satellite, CNRS, 29 rue J. Marvig, 31055 Toulouse Cedex, France
(2) Northwestern University, Department of Chemistry, 2145 Sheridan Road, Evanston, IL, 60208-3113, USA

Abstract
From the bottom, it is demonstrated how all the known intramolecular single-molecule logic gate architectures – semi-classical circuits, quantum Hamiltonian circuits, and qubit circuits – are different versions of the quantum control of intramolecular processes. They only differ in the way the classical input data are encoded on the quantum molecular system and how the quantum-to-classical conversion proceeds to read the output.

Methylterrylene isomers

TETRAHEDRON 68, 9371-9375 (2012)

Authors
Samuthira Nagarajany, Cecile Barthesz, NavdeepK. Girdharx, Tung T.Dang, Andre Gourdon (1)
(1) NanoSciences Group, CEMES, CNRS, UPS, BP94347, 29 Rue Jeanne Marvig, 31055 Toulouse Cedex 04, France

Abstract
2-Methyl and 3-methylterrylenes have been obtained by Suzuki coupling of 3-bromoperylene and corresponding methylnaphthylboronic acids or esters, giving methylnaphthylperylene isomers, followed by Scholl cyclodehydrogenation; the latter reaction gave also the other cyclodehydrogenation isomers 10- (respectively, 9-) methylbenzo[4,5]indeno[1,2,3-cd]perylene.

Gold for the Generation and Control of Fluxional Barbaralyl Cations

ANGEW.CHEM.INT.Ed.,51,1–5 (2012)

Authors
Dr. Paul R. McGonigal(1), Claudia de León(1), Yahui Wang(1), Anna Homs(1), César R. Solorio-Alvarado(1), Prof. Antonio M. Echavarren(1,2)
(1) Institute of Chemical Research of Catalonia (ICIQ), Av. Països Catalans 16, 43007 Tarragona (Spain) (2) Departament de Química Analítica i Química Orgànica, Universitat Rovira i Virgili, C/Marcel·li Domingo s/n, 43007 Tarragona (Spain)

Abstract
The frog prince with his two identities pales in comparison with the shape-shifting barbaralyl cation, which exists as a mixture of 181 400 degenerate forms. Gold-catalyzed cycloisomerizations of 7-alkynyl cyclohepta-1,3,5-trienes were found to proceed via fluxional barbaralyl intermediates (see scheme). The evolution of the intermediates into 1- or 2-substituted indenes could be controlled by the choice of gold.


Energetics and stability of dangling-bond silicon wires on H passivated Si(100)

J. PHYS. COND. MAT 24, 445005 (2012)

Authors R Robles (1), M Kepenekian (1), S Monturet (2), C Joachim (2) and N Lorente (1)
(1) Centro de Investigacion en Nanociencia y Nanotecnologia, CIN2 (CSIC–ICN), Campus de la UAB, E-08193 Bellaterra, Spain
(2) Centre d’Elaboration des Materiaux et d’Etudes Structurales (CEMES) and MANA Satellite, CNRS,29 rue J Marvig, F-31055 Toulouse, Cedex, France

Abstract
We evaluate the electronic, geometric and energetic properties of quasi 1D wires formed by dangling-bonds on Si(100)-H(2 × 1). The calculations are performed with density functional theory (DFT). Infinite wires are found to be insulating and Peierls distorted, however finite wires develop localized electronic states that can be of great use for atomic scale devices. The ground state solution of finite wires does not correspond to a geometrical distortion but rather to an antiferromagnetic ordering. For the stability of wires, the presence of abundant H atoms in nearby Si atoms can be a problem. We have evaluated the energy barriers for intradimer and intrarow diffusion, finding all of them about 1 eV or larger, even in the case where a H impurity is already sitting on the wire. These results are encouraging for using dangling-bond wires in future devices.

Dangling bond logic gates on the Si(100)-(2x1)-H surface

J. PHYS. COND. MAT., 24, 095011 (2012)

Authors
H. Kawai (1), F.Ample (1), W. Qing (2), Y.K.Yeo (1,2), M. Saeys (1,2), and C. Joachim(1,3)
(1) Institute of Materials Research and Engineering, 3 Research Link, Singapore 117602, Singapore
(2) Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117576, Singapore
(3) Nanosciences Group & MANA Satellite, CEMES-CNRS, 29 rue Jeanne Marvig, F-31055 Toulouse, France

Abstract
Atomic-scale Boolean logic gates (LGs) with two inputs and one output (i.e. OR, NOR, AND, NAND) were designed on a Si(100)-(2 × 1)–H surface and connected to the macroscopic scale by metallic nano-pads physisorbed on the Si(100)-(2 × 1)–H surface. The logic inputs are provided by saturating and unsaturating two surface Si dangling bonds, which can, for example, be achieved by adding and extracting two hydrogen atoms per input. Quantum circuit design rules together with semi-empirical elastic-scattering quantum chemistry transport calculations were used to determine the output current intensity of the proposed switches and LGs when they are interconnected to the metallic nano-pads by surface atomic-scale wires. Our calculations demonstrate that the proposed devices can reach ON/OFF ratios of up to 2000 for a running current in the 10 µA range.



Surface-State Engineering for Interconnects on H Passivated Si(100)

NanoLett., 13, 1192−1195 (2013)

Authors Mikael Kepenekian,*, † Roberto Robles,† Christian Joachim,‡,§ and Nicolas Lorente
†† Centro de Investigacion en Nanociencia y Nanotecnología CIN2 (CSIC-ICN), Campus de la UAB, E-08193 Bellaterra, Spain
‡ GNS & MANA Satellite, Centre d’Elaboration des Materiaux et d’Etudes Structurales (CEMES), CNRS, 29 rue J. Marvig, 31055 Toulouse Cedex, France
§ Institute of Materials Research and Engineering, 3 Research Link, Singapore 117602, Singapore

Abstract
Surface-state engineering strategies for atomic-size interconnects on H-passivated Si(100) surfaces are explored. The well-known simple interconnect formed by removing H-atoms from one of the Si atoms per dimer of a dimer row along the Si(100) surface is poorly conducting. This is because one-dimensional-like instabilities open electronic gaps. Here, we explore two strategies to reduce the instabilities: spacing the dangling bonds with H atoms and changing the geometry by increasing the lateral size of the wires. The resulting wires are evaluated using density functional theory. Surprisingly, zigzag dangling-bond wires attain atomically con fined conduction properties comparable with the conduction of free-standing metallic monatomic wires. These results hint at band-engineering strategies for the development of electronically driven nanocircuits.


Construction of atomic-scale logic gates on a surface of hydrogen passivated germanium

Microelectronic Engineering 109 (2013) 262–265

Authors Marek Kolmer (a), Szymon Godlewski (a), Jakub Lis (a), Bartosz Such (a), Lev Kantorovich (b), Marek Szymonski (a)
a Centre for Nanometer-Scale Science and Advanced Materials, NANOSAM, Faculty of Physics, Astronomy, and Applied Computer Science, Jagiellonian University, Reymonta Str. 4,PL 30-059 Krakow, Poland
b Department of Physics, King’s College London, Strand, London WC2R 2LS, United Kingdom

Abstract

We describe a complete protocol for atomically precise dangling bond (DB) logic gate construction on a hydrogenated Ge(001):H surface. Starting from the preparation of the reconstructed Ge(001) surface followed by its passivation with hydrogen atoms we end up with the platform for scanning tunnelingmicroscopy (STM) atomic-scale lithography. Finally with the use of dimer-by-dimer STM tip-induced hydrogen desorption from the Ge(001) _ (2 _ 1):H surface the DB nanostructures of pre-designed form are fabricated. Furthermore, the STM tip manipulation provides the control over the buckling phase of a single DB dimer incorporated into the DB logic gate structure, which is of crucial importance for the final electronic properties of the system. Our results prove feasibility of DB atomic scale logic gate implementation on the passivated semiconductor surfaces.


A Controlled Quantum SWAP Logic Gate in a 4-center Metal Complex

Architecture and Design of Molecule Logic Gates and Atom Circuits, Springer Series Advances in Atom and Single Molecule Machines: ISBN: 978-3-642-33136-7 (2013) pages 237-247.

Authors Mohamed Hliwa (a), Jacques Bonvoisin (b), and Christian Joachim (b)
(a) Faculty of Sciences Ben M’Sik, University Hassan II-Mohammedia-Casablanca, BP 7955-Sidi Othman, Casablanca, Maroc. Nanoscience Groupe and MANA Satellite, CEMES/CNRS, 29 rue Jeanne Marvig, 31055, Toulouse, France
(b) Nanoscience Groupe and MANA Satellite, CEMES/CNRS, 29 rue Jeanne Marvig, 31055, Toulouse, France

Abstract

A monomolecular four center low spin paramagnetic organometallic complex is proposed and theoretically studied to work as a controlled quantum swap molecule logic gate. The magnetic super-exchange interaction between the 2 intramolecular qubits depends on the oxydation state of a third intermediate center itself controlled by an intervalence electron transfer process. A model system is build up using entangled spin qubits in the framework of an Heisenberg-Dirac-Van Vleck like spin Hamiltonian demonstrating the effective swapping operation of this complex.

Binary Full Adder in a Single Quantum System

Architecture and Design of Molecule Logic Gates and Atom Circuits, Springer Series Advances in Atom and Single Molecule Machines: ISBN: 978-3-642-33136-7 (2013) pages 221-234.

Authors N. Renaud (a) and C. Joachim (b)
(a) Non-Equilibrium Energy Research Center, Northwestern University, 2145 Sheridan Road, 60201,Evanston, USA
(b) CEMES-CNRS 29 rue Jeanne Marvig, BP 94347, 31055 Toulouse Cedex 4, France

Abstract

In this short book chapter we show how to implement a complex Boolean function in a simple quantum system using the quantum Hamiltonian computing approach (QHC) [Ref: J. Phys. A: Math. Theor. 44 (2011) 155302 (15pp)]. Following the QHC approach, the logical inputs are encoded in local modifications of the system’s Hamiltonian, and the outputs are read in the oscillation frequency of the population of well-defined target states. Few simple examples are presented first introducing a graphical aid that facilitates the design of QHC circuits. Using this graphical analogue to our symbolic analysis, we demonstrate how to easily implement multiple-inputs multiple-outputs logic gates taking benefit from the superposition principle. A binary full-adder is presented using this generalization of the QHC approach. We also show that using their nonlocal effect, each logical input needs to appear only once in the system and that different logical outputs are computed simultaneously.

Classical Logic in a Single Molecule

Architecture and Design of Molecule Logic Gates and Atom Circuits, Springer Series Advances in Atom and Single Molecule Machines: ISBN: 978-3-642-33136-7 (2013) pages 109-121.

Authors Mohamed Hliwa (a) and Christian Joachim (b)
(a) Faculty of Sciences Ben M’Sik, University Hassan II-Mohammedia-Casablanca, BP 7955-Sidi Othman, Casablanca, Maroc. Nanoscience Groupe and MANA Satellite, CEMES/CNRS, 29 rue Jeanne Marvig, 31055, Toulouse, France
(b) Nanoscience Groupe and MANA Satellite, CEMES/CNRS, 29 rue Jeanne Marvig, 31055,Toulouse, France

Abstract

The mesh and node circuit rules required to design an intramolecular electronic circuit are discussed. Adapting a standard diode logic circuit structure, OR, AND and XOR unimolecular logic gates are designed. The full multichannel electronic scattering matrix of those molecule circuits are calculated using our EHMO-NESQC technique [1] in accordance with those new quantum circuit superposition rules [2] and taking into account the chemisorption of the molecule on the contacting pads at the end of the input branches. For a Molecule-XOR gate to work, a non-linear transduction effect was introduced using a semiclassical model [10, 11] to describe the inelastic coupling between the electron transfer process through the molecule-XOR and the soft molecule conformation mode used to generate the XOR truth table. The calculated logic surface is very close to the ideal XOR Boolean truth table. We also report another application of our node and mesh intramolecular circuit laws [2] in balancing a 4-branch molecule Wheatstone bridge.

Dangling-Bond Wire Circuits on a Si(001)-(2x1):H Surface with Their Contacting Nanopads

Architecture and Design of Molecule Logic Gates and Atom Circuits, Springer Series Advances in Atom and Single Molecule Machines: ISBN: 978-3-642-33136-7 (2013) pages 163-174.

Authors Francisco Ample (a), Hiroyo Kawai (a), Kian Soon Yong (a),Mark Saeys (b),Kuan Eng Johnson Goh (a), and Christian Joachim (c)
(a) Institute of Materials Research and Engineering, 3 Research Link, Singapore 117602
(b) Institute of Materials Research and Engineering, 3 Research Link, Singapore 117602 Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive, Singapore 117576
(c) Institute of Materials Research and Engineering, 3 Research Link, Singapore 117602 Nanosciences Group & MANA Satellite, CEMES-CNRS, 29 rue Jeanne Marvig, F-31055 Toulouse, France

Abstract

Electron transport through atomic-scale circuits made of dangling-bond (DB) wires is discussed using the N-ESQC technique taking also into account the contacting nanopads on the circuits. The band structure of the Si(001)-(2x1):H surface is analyzed together with the ones with infinite dangling-bond wires. The exponential decay in the conductance when tunneling between two atomic wires through the hydrogenated Si(001) surface shows two different rates depending of the tunneling direction. Taking advantage of this difference in the decay rate, an efficient OR DB logic gate is presented.When the DB is connected to metallic nanopads, the circuit is behaving like a quantum box with states resonating as captured by its electronic transmission spectrum. The through-surface leakage current between the nanopads is also evaluated. Finally and in the tunneling regime, the DB electronic circuit rules are discussed using series and parallel surface circuits.

Dangling-Bond Logic: Designing Boolean Logic Gates on a Si(001)-(2x1):H Surface

Architecture and Design of Molecule Logic Gates and Atom Circuits, Springer Series Advances in Atom and Single Molecule Machines: ISBN: 978-3-642-33136-7 (2013), pages 149-174.

Authors Hiroyo Kawai (a), Francisco Ample (a), Christian Joachim (b), and Mark Saeys (c)
(a) Institute of Materials Research and Engineering, 3 Research Link, Singapore 117602
(b) Institute of Materials Research and Engineering, 3 Research Link, Singapore 117602 Nanosciences Group & MANA Satellite, CEMES-CNRS, 29 rue Jeanne Marvig, F-31055 Toulouse, France
(c) Institute of Materials Research and Engineering, 3 Research Link, Singapore 117602 Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117576

Abstract

Atomic-scale dangling-bondBoolean logic gates with two inputs and one output are designed on a Si(001)-(2x1):H surface. The dangling-bond logic gates are connected to the macroscopic scale by metallic nano-electrodes physisorbed on the Si(100)-(2x1):H surface. The logic inputs are provided by saturating and unsaturating surface Si dangling bonds, which can, for example, be achieved by adding and extracting two hydrogen atoms per input. Quantum-transport calculations were used to investigate the operation of the proposed dangling-bond logic gates interconnected to the metallic nano-electrodes by surface dangling-bond wires. Our calculations indicate that the proposed dangling-bond logic devices can reach ON/OFF ratios up to 2000.

First-Principles Simulations of Electronic Transport in Dangling-Bond Wires

Architecture and Design of Molecule Logic Gates and Atom Circuits, Springer Series Advances in Atom and Single Molecule Machines: ISBN: 978-3-642-33136-7 (2013) pages 137-148

Authors M. Kepenekian, R. Robles, and N. Lorente
Centro de Investigacion en Nanociencia y Nanotecnologıa, CSIC-ICN,E-08193 Bellaterra, Spain

Abstract

It has recently become possible to calculate at an ab initio level electronic transport in atomic and molecular systems connected to semi-infinite electrodes under an applied bias. In this chapter, we show how electronic structure calculations based on the density functional theory (DFT), followed by the use of nonequilibrium Green’s functions (NEGF), allow one to simulate the electronic transport in various systems. This method is apply to the problem of electronic transport in danglingbond wires built on the Si(100) surface.

Theory of Inelastic Transport Through Atomic SurfaceWires

Architecture and Design of Molecule Logic Gates and Atom Circuits, Springer Series Advances in Atom and Single Molecule Machines: ISBN: 978-3-642-33136-7 (2013), pages 175-185.

Authors Serge Monturet and Christian Joachim
CEMES/CNRS, 29 rue Jeanne Marvig, 31055, Toulouse, France

Abstract

With the help of state-of-the-art local probe microscopy together with the capability of synthetic chemistry to produce a wide swathe of molecules, the functionalization of adsorbed species on surfaces can be achieved; they can notably play the role of logic gates[1, 2]. To contact them, nanoscale wires have been studied both experimentally [3] and theoretically [4, 5] regarding their structural and electronic properties. However, the role that inelastic effects may play during the transport through these wires is still an open question. The aim of this chapter is to give an overview of the theoretical methods that can be set up to elucidate the problem of mechanical heating of the surface atomic wires by conduction electrons.

Electronic Transmission Through a Single Impurity in a Multi-configuration Scattering Matrix Approach

Proceedings of the 3rd AtMol International Workshop, Berlin 24-25 September 2012, “Imaging and Manipulating Molecular Orbitals” Advances in Atom and Single Molecule Machines - Series Editor: Christian Joachim, Springer, ISBN: 978-3-642-38808-8 (2013) pages 137-157.

Authors M. Portais and C. Joachim
Centre d’Elaboration de Matriaux et d’Etudes Structurales (CEMES-CNRS), 29 rue Jeanne Marvig 31055 Toulouse Cedex 4, BP 94347, France

Abstract

A method is presented to calculate the scattering matrix of holes and electrons scattered by a molecular tunnel junction in a multi-configurational electronic approach. This is applicable for atomic scale systems where holes and electrons are delivered to the junction by metallic electrodes functioning in a ballistic regime of transport and where the full electronic structure of the molecular junction is considered. Applications of this CI-ESQC calculation technique demonstrates that the scattering resonances are built up from the superposition multi configurational electronic states describing the virtual reduced or oxidized states of the molecular junction during the scattering process.

High Voltage STM Imaging of Single Copper Phthalocyanine

Architecture and Design of Molecule Logic Gates and Atom Circuits, Springer Series Advances in Atom and Single Molecule Machines: ISBN: 978-3-642-38808-8 (2013), pages 15-26.

Authors C. Manzano (a), W.-H. Soe (a) and C. Joachim (b)
(a) IMRE, Agency for Science, Technology and Research (A*STAR), 3 Research Link 117602 Singapore, Singapore
(b) CEMES/CNRS, Pico Lab, 29 Rue Marvig, BP 94347 31055 Toulouse Cedex, France

Abstract

In this chapter experiments done to investigate the scanning tunneling microscope (STM) imaging at near field emission voltages of single Copper Phthalocyanine (CuPc) molecules deposited on Au(111) are presented. An imaging bias voltage range is explored exceeding the standard tunneling imaging conditions going from the threshold of the tunneling junction barrier up to - 10.0 V. At this voltage regime current transmitted through the tip-molecule– substrate junction is made not only of tunneling electrons but also of electrons overcoming the tunneling barrier and behaving like free electrons. Our interpretation of the process, enabling the visualization of the electronic cloud of single organic molecules under these conditions, is presented.


Mapping the Electronic Resonances of Single Molecule STM Tunnel Junctions

Architecture and Design of Molecule Logic Gates and Atom Circuits, Springer Series Advances in Atom and Single Molecule Machines: ISBN: 978-3-642-38808-8 (2013), pages 57-67.

Authors We-Hyo Soe (a), Carlos Manzano (a) and Christian Joachim (a,b)
(a) IMRE, Agency for Science, Technology and Research (A*STAR), 3 Research Link 117602 Singapore, Singapore
(b) CEMES/CNRS, Pico Lab, 29 Rue Marvig, BP 94347 31055 Toulouse Cedex, France

Abstract

In this chapter is presented how the electron probability distributions of molecular states are imaged in real space using scanning tunneling microscopy. Differential tunneling conductance images of selected single molecules taken at voltages corresponding to resonances near the substrate Fermi level were found to be very close to their respective mono-electronic molecular orbitals. In contrast, high-order resonance states images were composed of molecular orbitals components from many states, even though those states lie in a lower energy range.

Simulations of Constant Current STM Images of Open-Shell Systems

Proceedings of the 3rd AtMol International Workshop, Berlin 24-25 September 2012, “Imaging and Manipulating Molecular Orbitals” Advances in Atom and Single Molecule Machines - Series Editor: Christian Joachim, Springer, ISBN: 978-3-642-38808-8 (2013) pages 117-136.

Authors M. Kepenekian (a), R. Robles (a), R. Korytár (a,b) and N. Lorente (a)
(a) Centro de Investigación en Nanociencia y Nanotecnología, CSIC-ICN, Bellaterra 08193, Spain
(b) Institut für Nanotechnologie, Karlsruher Institut für Technologie, Hermann-von-Helmholtzplatz 1, 76344 Eggenstein-Leopoldshafen, Germany

Abstract

In this chapter we review the main methods for simulating STM images, mainly the Tersoff–Hamman approximation based on the Bardeen approach and full-fledge Landauer calculations based on nonequilibrium Green’s functions (NEGF). However, these methods are built on the electronic structure of the system as computed by density functional theory (DFT). This theory has important limitation for open-shell systems. As a matter of fact, an open-shell molecule on a metallic substrate can lead to correlations among the electrons of the metal. This gives rise to the Kondo effect. Hence, we briefly present a method to implement STM image simulations including the Kondo effect.

Observations of Individual Cu-Phthalocyanine Molecules Deposited on Nano-Tips in the Field Emission Microscope

Architecture and Design of Molecule Logic Gates and Atom Circuits, Springer Series Advances in Atom and Single Molecule Machines: ISBN: 978-3-642-38808-8 (2013), pages 3-13.

Authors Moh’d Rezeq (a), Christian Joachim (b,c), Ma Han Lwin (d) and Francisco Ample Navarro (b)
(a) Khalifa University of Science Technology and Research (KUSTAR), POB 127788, Abu Dhabi, UAE
(b) Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 3 Research Link, 117602 Singapore, Singapore
(c) Nanoscience Group and MANA Satellite, CEMES/CNRS, 29 Rue Marvig, BP 94347, 31055 Toulouse Cedex, France
(d) Formerly of IMRE, Singapore, Singapore

Abstract

Using a field emission microscope (FEM), the first image ever of isolated individual molecules was reported in the 1950s. At that time, the Cu-Phthalocyanine (Cu-Pc) molecule was imaged in different configurations, namely two- and four-leaf patterns. These various apparent shapes were linked to the location of the molecule on particular atomic planes of the relatively quite large FEM tip apex used at that time. We report here on how the fabrication of an extremely sharp FEM tip with an apex of the size of the molecule to be imaged provides a unique opportunity to study the behavior of one molecule at a time on the tip apex. Preliminary data are presented where two adsorption states have been observed according to the electronic cloud FEM images of the molecule. Since the atomic structure of the tip can be determined first from a field ion microscope image, the interaction of the molecule with tip apex surface atoms, and thus the molecule adsorption conformation can be readily determined.

Vibrational transition rule during a through-bond electron transfer Process

CHEMICAL PHYSICS LETTERS 567 ; 1–5 (2013)

Authors Serge Monturet (a), Mikaël Kepenekian (b), Roberto Robles (b), Nicolás Lorente (b), Christian Joachim (a)
(a) Nanoscience Group & MANA Satellite, CEMES/CNRS, 29 Rue Jeanne Marvig, 31055 Toulouse, France
(b) Centre d’Investigació en Nanociència i Nanotecnologia CIN2 (ICN-CSIC), UAB Campus, E-08193 Bellaterra, Spain

Abstract

The transition rule governing the inelastic excitations of molecular vibrations occurring during a molecular through-state electron transfer process is presented. Using an effective Hamiltonian model, it is shown that the quantum time oscillation of the intermediate electronic state population triggers this transition. Its corresponding quantum oscillation frequency has to be equal to a quantum of vibration. This transition rule is extended to the full spectrum of a quantum vibrator. This new transition rule is expected to be robust when electronically coupling the molecule to the metallic pads of a voltage-biased tunnel junction.

Thermally and Vibrationally Induced Tautomerization of Single Porphycene Molecules on a Cu(110) Surface

PRL 111, 246101 (2013).246101

Authors
Takashi Kumagai,(1) Felix Hanke,(2) Sylwester Gawinkowski,(3) John Sharp,(2) Konstantinos Kotsis,(2) Jacek Waluk,(3) Mats Persson,(2,4) and Leonhard Grill(1,5)
(1) Department of Physical Chemistry, Fritz-Haber Institute of the Max-Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
(2) Surface Science Research Centre and Department of Chemistry, University of Liverpool, Liverpool L69 3BX, United Kingdom
(3) Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
(4) Department of Applied Physics, Chalmers University of Technology, 41296 Goteborg, Sweden
(5) Department of Physical Chemistry, University of Graz, Heinrichstrasse 28, 8010 Graz, Austria
(Received 3 September 2013; published 11 December 2013)

Abstract
We report the direct observation of intramolecular hydrogen atom transfer reactions (tautomerization) within a single porphycene molecule on a Cu(110) surface by scanning tunneling microscopy. It is found that the tautomerization can be induced via inelastic electron tunneling at 5 K. By measuring the biasdependent tautomerization rate of isotope-substituted molecules, we can assign the scanning tunneling microscopy-induced tautomerization to the excitation of specific molecular vibrations. Furthermore, these vibrations appear as characteristic features in the dI=dV spectra measured over individual molecules. The vibrational modes that are associated with the tautomerization are identified by density functional theory calculations. At higher temperatures above _75 K, tautomerization is induced thermally and an activation barrier of about 168 meV is determined from an Arrhenius plot.

Manipulation and Spectroscopyof Individual Phthalocyanine Molecules on InAs(111)A with a Low-Temperature Scanning Tunneling Microscope

Proceedings of the 3rd AtMol International Workshop, Berlin 24-25 September 2012, “Imaging and Manipulating Molecular Orbitals” Advances in Atom and Single Molecule Machines - Series Editor: Christian Joachim, Springer, ISBN: 978-3-642-38808-8 (2013) pages 69-79.

Authors

Christophe Nacci (a,c), Kiyoshi Kanisawa (b) and Stefan Fölsch (a)
(a)  Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7 10117 Berlin, Germany
University, Reymonta Str. 4, PL 30-059 Krakow, Poland
(b)  NTT Basic Research Laboratories, NTT Corporation, Atsugi, Kanagawa 243-0198, Japan
(c) Fritz-Haber-Institut der Max-Planck-Gesellschaft, Abteilung für Physikalische Chemie, Faradayweg 4-6 14195 Berlin, Germany

Abstract
Single free-base phthalocyanine (H2Pc), copper phthalocyanine (CuPc), and naphthalocyanine (NPc) molecules on the III-V semiconductor surface InAs(111)A-(2 9 2) were investigated by cryogenic scanning tunneling microscopy (STM) at 5 K. STM imaging of largely unperturbed frontier orbitals of NPc on InAs(111)A reveals that the molecule is physisorbed. In the adsorbed state, the molecular electronic structure of NPc is preserved to a large extent, indicating a weak electronic coupling to the underlying substrate surface. As a free molecule, H2Pc is bistable because of an internal hydrogen transfer reaction (tautomerization). When adsorbed on the InAs(111)A surface, H2Pc experiences rotational fluctuations about its center because of excitations induced by inelastic electron tunneling (IET). STM-based atom and molecule manipulation techniques were used to sterically hinder the molecular rotation by assembling In adatom-molecule complexes, facilitating to probe the hydrogen transfer reaction in a controlled way. STM imaging of the Inad-H2Pc-Inad complex clearly reveals the presence of a lefthanded and a right-handed conformer, indicating that the H2Pc tautomerization is left unperturbed by the substrate and the pinning adatoms, and that it can be triggered by the tunneling electrons.

Quantifying the atomic-level mechanics of single long physisorbed molecular chains

PNAS March 18, (2014) vol. 111 no. 11 3968–3972

Authors

Shigeki Kawaia (b), Matthias Koch (c), Enrico Gnecco (d), Ali Sadeghi (a), Rémy Pawlak (a), Thilo Glatzel (a), Jutta Schwarz (e), Stefan Goedecker (a), Stefan Hecht (e), Alexis Baratoff (a), Leonhard Grill (c,f), and Ernst Meyer (a)

(a)  Department of Physics, University of Basel, 4056 Basel, Switzerland;
(b)  Precursory Research for Embryonic Science, Japan Science and Technology Agency, 4056 Basel, Switzerland
(c)  Department of Physical Chemistry, Fritz Haber Institute of the Max Planck Society, 14195 Berlin, Germany
(d)  Instituto Madrileño de Estudios Avanzados en Nanociencia, 28049 Madrid, Spain
(e)  Department of Chemistry, Humboldt-Universität zu Berlin, 12489 Berlin, Germany
(f)  Department of Physical Chemistry, University of Graz, 8010 Graz, Austria

Abstract
Individual in situ polymerized fluorene chains 10–100 nm long linked by C–C bonds are pulled vertically from an Au(111) substrate by the tip of a low-temperature atomic force microscope. The conformation of the selected chains is imaged before and after manipulation using scanning tunneling microscopy. The measured force gradient shows strong and periodic variations that correspond to the step-by-step detachment of individual fluorine repeat units. These variations persist at constant intensity until the entire polymer is completely removed from the surface. Calculations based on an extended Frenkel–Kontorova model reproduce the periodicity and magnitude of these features and allow us to relate them to the detachment force and desorption energy of the repeat units. The adsorbed part of the polymer slides easily along the surface during the pulling process, leading to only small oscillations as a result of the high stiffness of the fluorenes and of their length mismatch with respect to the substrate surface structure. A significant lateral force also is caused by the sequential detachment of individual units. The gained insight into the molecule– surface interactions during sliding and pulling should aid the design of mechano responsive nanosystems and devices.

Gold(I) Carbenes by Retro-Buchner Reaction: Generation and Fate

J. Am. Chem. Soc. (2014), 136, 801−809

Authors Yahui Wan(a), Paul R. McGonigal (a), Bart Herlé (a), Maria Besora (a) and Antonio M. Echavarren(a, b)

(a)  Institute of Chemical Research of Catalonia (ICIQ), Av. Paísos Catalans 16, 43007 Tarragona, Spain
(b)  Departament de Química Analítica i Química Orgànica, Universitat Rovira i Virgili, C/Marcel·li Domingo s/n, 43007 Tarragona, Spain

Abstract

The fate of the aryl gold (I) carbenes generated by retro-Buchner reaction of ortho-substituted 7-aryl-1,3,5- cycloheptatrienes is dependent on the constitution of the ortho substituent. Indenes and fluorenes are obtained by intramolecular reaction of highly electrophilic gold (I) carbenes with alkenes and arenes. According to density functional theory calculations, the gold-catalyzed retro-Buchner process occurs stepwise, although the two carbon−carbon cleavages occur on a rather flat potential energy surface.


Spin transport in dangling-bond wires on doped H-passivated Si(100)

IOP Publishing Nanotechnology 25 (2014) 465703 (6pp)

Authors Mikaël Kepenekian(1,2), Roberto Robles(2,3), Riccardo Rurali(4) and Nicolás Lorente(2,3)

1.- Institut des Sciences Chimiques de Rennes UMR 6226, CNRS–Université de Rennes 1, Rennes, France
2.- ICN2–Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra (Barcelona), Spain
3.- CSIC–Consejo Superior de Investigaciones Cientificas, ICN2 Building, Campus UAB, 08193 Bellaterra (Barcelona), Spain
4.- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus de Bellaterra, 08193 Bellaterra (Barcelona), Spain

Abstract

New advances in single-atom manipulation are leading to the creation of atomic structures on Hpassivated Si surfaces with functionalities important for the development of atomic and molecular based technologies. We perform total-energy and electron-transport calculations to
reveal the properties and understand the features of atomic wires crafted by H removal from thesurface. The presence of dopants radically change the wire properties. Our calculations show thatdopants have a tendency to approach the dangling-bond wires, and in these conditions, transportis enhanced and spin selective. These results have important implications in the development ofatomic-scale spintronics showing that boron, and to a lesser extent phosphorous, convert thewires in high-quality spin filters.