1
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Chen Y, Bâldea I, Yu Y, Liang Z, Li MD, Koren E, Xie Z. CP-AFM Molecular Tunnel Junctions with Alkyl Backbones Anchored Using Alkynyl and Thiol Groups: Microscopically Different Despite Phenomenological Similarity. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:4410-4423. [PMID: 38348971 PMCID: PMC10906003 DOI: 10.1021/acs.langmuir.3c03759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 01/24/2024] [Accepted: 01/24/2024] [Indexed: 02/28/2024]
Abstract
In this paper, we report results on the electronic structure and transport properties of molecular junctions fabricated via conducting probe atomic force microscopy (CP-AFM) using self-assembled monolayers (SAMs) of n-alkyl chains anchored with acetylene groups (CnA; n = 8, 9, 10, and 12) on Ag, Au, and Pt electrodes. We found that the current-voltage (I-V) characteristics of CnA CP-AFM junctions can be very accurately reproduced by the same off-resonant single-level model (orSLM) successfully utilized previously for many other junctions. We demonstrate that important insight into the energy-level alignment can be gained from experimental data of transport (processed via the orSLM) and ultraviolet photoelectron spectroscopy combined with ab initio quantum chemical information based on the many-body outer valence Green's function method. Measured conductance GAg < GAu < GPt is found to follow the same ordering as the metal work function ΦAu < ΦAu < ΦPt, a fact that points toward a transport mediated by an occupied molecular orbital (MO). Still, careful data analysis surprisingly revealed that transport is not dominated by the ubiquitous HOMO but rather by the HOMO-1. This is an important difference from other molecular tunnel junctions with p-type HOMO-mediated conduction investigated in the past, including the alkyl thiols (CnT) to which we refer in view of some similarities. Furthermore, unlike in CnT and other junctions anchored with thiol groups investigated in the past, the AFM tip causes in CnA an additional MO shift, whose independence of size (n) rules out significant image charge effects. Along with the prevalence of the HOMO-1 over the HOMO, the impact of the "second" (tip) electrode on the energy level alignment is another important finding that makes the CnA and CnT junctions different. What ultimately makes CnA unique at the microscopic level is a salient difference never reported previously, namely, that CnA's alkyne functional group gives rise to two energetically close (HOMO and HOMO-1) orbitals. This distinguishes the present CnA from the CnT, whose HOMO stemming from its thiol group is well separated energetically from the other MOs.
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Affiliation(s)
- Yuhong Chen
- Department
of Materials Science and Engineering, Technion-Israel
Institute of Technology, Haifa 3200003, Israel
- Department
of Materials Science and Engineering, Guangdong Provincial Key Laboratory
of Materials and Technologies for Energy Conversion (MATEC), Guangdong Technion-Israel Institute of Technology, 241 Daxue Road, Shantou, Guangdong 515063, China
| | - Ioan Bâldea
- Theoretical
Chemistry, Heidelberg University, Im Neuenheimer Feld 229, D-69120 Heidelberg, Germany
| | - Yongxin Yu
- Department
of Materials Science and Engineering, Guangdong Provincial Key Laboratory
of Materials and Technologies for Energy Conversion (MATEC), Guangdong Technion-Israel Institute of Technology, 241 Daxue Road, Shantou, Guangdong 515063, China
| | - Zining Liang
- Department
of Materials Science and Engineering, Guangdong Provincial Key Laboratory
of Materials and Technologies for Energy Conversion (MATEC), Guangdong Technion-Israel Institute of Technology, 241 Daxue Road, Shantou, Guangdong 515063, China
| | - Ming-De Li
- Department
of Chemistry and Key Laboratory for Preparation and Application of
Ordered Structural Materials of Guangdong Province, Shantou University, Shantou 515063, China
| | - Elad Koren
- Department
of Materials Science and Engineering, Technion-Israel
Institute of Technology, Haifa 3200003, Israel
| | - Zuoti Xie
- Department
of Materials Science and Engineering, Technion-Israel
Institute of Technology, Haifa 3200003, Israel
- Department
of Materials Science and Engineering, Guangdong Provincial Key Laboratory
of Materials and Technologies for Energy Conversion (MATEC), Guangdong Technion-Israel Institute of Technology, 241 Daxue Road, Shantou, Guangdong 515063, China
- Quantum
Science Center of Guangdong-Hong Kong-Macao Greater Bay Area (Guangdong), Shenzhen-Hong Kong International Science and Technology
Park, No. 3 Binglang
Road, Futian District, Shenzhen, Guangdong 518048, China
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2
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Paoletta AL, Venkataraman L. Determining Transmission Characteristics from Shot-Noise-Driven Electroluminescence in Single-Molecule Junctions. NANO LETTERS 2024; 24:1931-1935. [PMID: 38315038 DOI: 10.1021/acs.nanolett.3c04207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
Biased metal-molecule-metal junctions emit light through electroluminescence, a phenomenon at the intersection of molecular electronics and nanoplasmonics. This can occur when the junction plasmon mode is excited by inelastic electron current fluctuations. Here, we simultaneously measure the conductance and electroluminescence intensity from single-molecule junctions with time resolution in a solution environment at room temperature. We use current versus bias data to determine the molecular junction transport parameters and then relate these to the expected current shot noise. We find that the electroluminescence signal accurately matches the theoretical prediction of shot-noise-driven emission in a large fraction of the molecular junctions studied. This introduces a novel experimental method for qualitatively estimating finite-frequency shot noise in single-molecule junctions under ambient conditions. We further demonstrate that electroluminescence can be used to obtain the level alignment of the frontier orbital dominating transport in the molecular junction.
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Affiliation(s)
- Angela L Paoletta
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Latha Venkataraman
- Department of Chemistry, Columbia University, New York, New York 10027, United States
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United States
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3
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Grall S, Li S, Jalabert L, Kim SH, Chovin A, Demaille C, Clément N. Electrochemical Shot Noise of a Redox Monolayer. PHYSICAL REVIEW LETTERS 2023; 130:218001. [PMID: 37295112 DOI: 10.1103/physrevlett.130.218001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 04/25/2023] [Indexed: 06/12/2023]
Abstract
Redox monolayers are the base for a wide variety of devices including high-frequency molecular diodes or biomolecular sensors. We introduce a formalism to describe the electrochemical shot noise of such a monolayer, confirmed experimentally at room temperature in liquid. The proposed method, carried out at equilibrium, avoids parasitic capacitance, increases the sensitivity, and allows us to obtain quantitative information such as the electronic coupling (or standard electron transfer rates), its dispersion, and the number of molecules. Unlike in solid-state physics, the homogeneity in energy levels and transfer rates in the monolayer yields a Lorentzian spectrum. This first step for shot noise studies in molecular electrochemical systems opens perspectives for quantum transport studies in a liquid environment at room temperature as well as highly sensitive measurements for bioelectrochemical sensors.
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Affiliation(s)
- Simon Grall
- IIS, LIMMS/CNRS-IIS IRL2820, The University of Tokyo, 4-6-1 Komaba, Meguro-ku Tokyo, 153-8505, Japan
| | - Shuo Li
- IIS, LIMMS/CNRS-IIS IRL2820, The University of Tokyo, 4-6-1 Komaba, Meguro-ku Tokyo, 153-8505, Japan
| | - Laurent Jalabert
- IIS, LIMMS/CNRS-IIS IRL2820, The University of Tokyo, 4-6-1 Komaba, Meguro-ku Tokyo, 153-8505, Japan
| | - Soo Hyeon Kim
- IIS, LIMMS/CNRS-IIS IRL2820, The University of Tokyo, 4-6-1 Komaba, Meguro-ku Tokyo, 153-8505, Japan
| | - Arnaud Chovin
- Université Paris Cité, CNRS, Laboratoire d'Electrochimie Moléculaire, F-75013 Paris, France
| | - Christophe Demaille
- Université Paris Cité, CNRS, Laboratoire d'Electrochimie Moléculaire, F-75013 Paris, France
| | - Nicolas Clément
- IIS, LIMMS/CNRS-IIS IRL2820, The University of Tokyo, 4-6-1 Komaba, Meguro-ku Tokyo, 153-8505, Japan
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4
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Balanced electron flow and the hydrogen bridge energy levels in Pt, Au, or Cu nanojunctions. APPLIED NANOSCIENCE 2022. [DOI: 10.1007/s13204-022-02537-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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5
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Shein-Lumbroso O, Liu J, Shastry A, Segal D, Tal O. Quantum Flicker Noise in Atomic and Molecular Junctions. PHYSICAL REVIEW LETTERS 2022; 128:237701. [PMID: 35749205 DOI: 10.1103/physrevlett.128.237701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Accepted: 05/02/2022] [Indexed: 06/15/2023]
Abstract
We report on a quantum form of electronic flicker noise in nanoscale conductors that contains valuable information on quantum transport. This noise is experimentally identified in atomic and molecular junctions and theoretically analyzed by considering quantum interference due to fluctuating scatterers. Using conductance, shot-noise, and flicker-noise measurements, we show that the revealed quantum flicker noise uniquely depends on the distribution of transmission channels, a key characteristic of quantum conductors. This dependence opens the door for the application of flicker noise as a diagnostic probe for fundamental properties of quantum conductors and many-body quantum effects, a role that up to now has been performed by the experimentally less-accessible shot noise.
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Affiliation(s)
- Ofir Shein-Lumbroso
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Junjie Liu
- Department of Chemistry and Centre for Quantum Information and Quantum Control, University of Toronto, 80 Saint George Street, Toronto, Ontario M5S 3H6, Canada
| | - Abhay Shastry
- Department of Chemistry and Centre for Quantum Information and Quantum Control, University of Toronto, 80 Saint George Street, Toronto, Ontario M5S 3H6, Canada
| | - Dvira Segal
- Department of Chemistry and Centre for Quantum Information and Quantum Control, University of Toronto, 80 Saint George Street, Toronto, Ontario M5S 3H6, Canada
- Department of Physics, 60 Saint George Street, University of Toronto, Toronto, Ontario M5S 1A7, Canada
| | - Oren Tal
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
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6
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Tamir I, Caspari V, Rolf D, Lotze C, Franke KJ. Shot-noise measurements of single-atom junctions using a scanning tunneling microscope. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:023702. [PMID: 35232162 DOI: 10.1063/5.0078917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 01/26/2022] [Indexed: 06/14/2023]
Abstract
Current fluctuations related to the discreteness of charge passing through small constrictions are termed shot noise. This unavoidable noise provides both advantages-being a direct measurement of the transmitted particles' charge-and disadvantages-a main noise source in nanoscale devices operating at low temperature. While better understanding of shot noise is desired, the technical difficulties in measuring it result in relatively few experimental works, especially in single-atom structures. Here, we describe a local shot-noise measurement apparatus and demonstrate successful noise measurements through single-atom junctions. Our apparatus, based on a scanning tunneling microscope, operates at liquid helium temperatures. It includes a broadband commercial amplifier mounted in close proximity to the tunnel junction, thus reducing both the thermal noise and input capacitance that limit traditional noise measurements. The full capabilities of the microscope are maintained in the modified system, and a quick transition between different measurement modes is possible.
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Affiliation(s)
- Idan Tamir
- Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
| | - Verena Caspari
- Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
| | - Daniela Rolf
- Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
| | - Christian Lotze
- Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
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7
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Fukuzumi R, Buerkle M, Li Y, Kaneko S, Li P, Kobayashi S, Fujii S, Kiguchi M, Nakamura H, Tsukagoshi K, Nishino T. Water Splitting Induced by Visible Light at a Copper-Based Single-Molecule Junction. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2008109. [PMID: 34089231 DOI: 10.1002/smll.202008109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Revised: 04/19/2021] [Indexed: 06/12/2023]
Abstract
Water splitting is an essential process for converting light energy into easily storable energy in the form of hydrogen. As environmentally preferable catalysts, Cu-based materials have attracted attention as water-splitting catalysts. To enhance the efficiency of water splitting, a reaction process should be developed. Single-molecule junctions (SMJs) are attractive structures for developing these reactions because the molecule electronic state is significantly modulated, and characteristic electromagnetic effects can be expected. Here, water splitting is induced at Cu-based SMJ and the produced hydrogen is characterized at a single-molecule scale by employing electron transport measurements. After visible light irradiation, the conductance states originate from Cu/hydrogen molecule/Cu junctions, while before irradiation, only Cu/water molecule/Cu junctions were observed. The vibration spectra obtained from inelastic electron tunneling spectroscopy combined with the first-principles calculations reveal that the water molecule trapped between the Cu electrodes is decomposed and that hydrogen is produced. Time-dependent and wavelength-dependent measurements show that localized-surface plasmon decomposes the water molecule in the vicinity of the junction. These findings indicate the potential ability of Cu-based materials for photocatalysis.
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Affiliation(s)
- Risa Fukuzumi
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Marius Buerkle
- CD-FMat, National Institute of Advanced Industrial Science and Technology (AIST), Central 2, Umezono 1-1-1, Tsukuba, Ibaraki, 305-8568, Japan
| | - Yu Li
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Satoshi Kaneko
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Peihui Li
- Institute of Modern Optics, Nankai University, 94 Weijin Road, Tianjin, 300350, P. R. China
| | - Shuji Kobayashi
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Shintaro Fujii
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Manabu Kiguchi
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Hisao Nakamura
- CD-FMat, National Institute of Advanced Industrial Science and Technology (AIST), Central 2, Umezono 1-1-1, Tsukuba, Ibaraki, 305-8568, Japan
| | - Kazuhito Tsukagoshi
- International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki, 305-0044, Japan
| | - Tomoaki Nishino
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan
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8
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Yuan S, Gao T, Cao W, Pan Z, Liu J, Shi J, Hong W. The Characterization of Electronic Noise in the Charge Transport through Single-Molecule Junctions. SMALL METHODS 2021; 5:e2001064. [PMID: 34927823 DOI: 10.1002/smtd.202001064] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 12/09/2020] [Indexed: 06/14/2023]
Abstract
With the goal of creating single-molecule devices and integrating them into circuits, the emergence of single-molecule electronics provides various techniques for the fabrication of single-molecule junctions and the investigation of charge transport through such junctions. Among the techniques for characterization of charge transport through molecular junctions, electronic noise characterization is an effective strategy with which issues from molecule-electrode interfaces, mechanisms of charge transport, and changes in junction configurations are studied. Electronic noise analysis in single-molecule junctions can be used to identify molecular conformations and even monitor reaction kinetics. This review summarizes the various types of electronic noise that have been characterized during single-molecule electrical detection, including the functions of random telegraph signal (RTS) noise, flicker noise, shot noise, and their corresponding applications, which provide some guidelines for the future application of these techniques to problems of charge transport through single-molecule junctions.
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Affiliation(s)
- Saisai Yuan
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering iChEM, Xiamen University, Xiamen, 361005, China
| | - Tengyang Gao
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering iChEM, Xiamen University, Xiamen, 361005, China
| | - Wenqiang Cao
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering iChEM, Xiamen University, Xiamen, 361005, China
| | - Zhichao Pan
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering iChEM, Xiamen University, Xiamen, 361005, China
| | - Junyang Liu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering iChEM, Xiamen University, Xiamen, 361005, China
| | - Jia Shi
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering iChEM, Xiamen University, Xiamen, 361005, China
| | - Wenjing Hong
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering iChEM, Xiamen University, Xiamen, 361005, China
- Beijing National Laboratory for Molecular Sciences, Beijing, 100190, China
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9
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Senkpiel J, Klöckner JC, Etzkorn M, Dambach S, Kubala B, Belzig W, Yeyati AL, Cuevas JC, Pauly F, Ankerhold J, Ast CR, Kern K. Dynamical Coulomb Blockade as a Local Probe for Quantum Transport. PHYSICAL REVIEW LETTERS 2020; 124:156803. [PMID: 32357030 DOI: 10.1103/physrevlett.124.156803] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Accepted: 03/24/2020] [Indexed: 06/11/2023]
Abstract
Quantum fluctuations are imprinted with valuable information about transport processes. Experimental access to this information is possible, but challenging. We introduce the dynamical Coulomb blockade (DCB) as a local probe for fluctuations in a scanning tunneling microscope (STM) and show that it provides information about the conduction channels. In agreement with theoretical predictions, we find that the DCB disappears in a single-channel junction with increasing transmission following the Fano factor, analogous to what happens with shot noise. Furthermore we demonstrate local differences in the DCB expected from changes in the conduction channel configuration. Our experimental results are complemented by ab initio transport calculations that elucidate the microscopic nature of the conduction channels in our atomic-scale contacts. We conclude that probing the DCB by STM provides a technique complementary to shot noise measurements for locally resolving quantum transport characteristics.
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Affiliation(s)
- Jacob Senkpiel
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Jan C Klöckner
- Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
- Fachbereich Physik, Universität Konstanz, 78457 Konstanz, Germany
| | - Markus Etzkorn
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Simon Dambach
- Institut für Komplexe Quantensysteme and IQST, Universität Ulm, Albert-Einstein-Allee 11, 89069 Ulm, Germany
| | - Björn Kubala
- Institut für Komplexe Quantensysteme and IQST, Universität Ulm, Albert-Einstein-Allee 11, 89069 Ulm, Germany
| | - Wolfgang Belzig
- Fachbereich Physik, Universität Konstanz, 78457 Konstanz, Germany
| | - Alfredo Levy Yeyati
- Departamento de Física Teórica de la Materia Condensada, Condensed Matter Physics Center (IFIMAC), and Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Juan Carlos Cuevas
- Departamento de Física Teórica de la Materia Condensada, Condensed Matter Physics Center (IFIMAC), and Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Fabian Pauly
- Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
- Fachbereich Physik, Universität Konstanz, 78457 Konstanz, Germany
| | - Joachim Ankerhold
- Institut für Komplexe Quantensysteme and IQST, Universität Ulm, Albert-Einstein-Allee 11, 89069 Ulm, Germany
| | - Christian R Ast
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Klaus Kern
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart, Germany
- Institut de Physique, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
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10
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Cohen G, Galperin M. Green’s function methods for single molecule junctions. J Chem Phys 2020; 152:090901. [DOI: 10.1063/1.5145210] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Affiliation(s)
- Guy Cohen
- The Raymond and Beverley Sackler Center for Computational Molecular and Materials Science, Tel Aviv University, Tel Aviv 69978, Israel
- School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
| | - Michael Galperin
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, USA
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11
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Tewari S, Sabater C, van Ruitenbeek J. Identification of vibration modes in single-molecule junctions by strong inelastic signals in noise. NANOSCALE 2019; 11:19462-19467. [PMID: 31528938 DOI: 10.1039/c9nr05774a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Conductance measurements in single-molecule junctions (SMJs) are on many occasions accompanied by inelastic spectroscopy and shot-noise measurements in order to obtain information about different vibration modes (or vibrons) and channels involved in the transport respectively. We have extended the single-molecule shot-noise measurements, which were previously performed at low bias, to high bias and we have studied the effects of these vibrons on the noise for a Deuterium (D2) molecule between Pt leads. We report here two important findings from these measurements. First, we find in our noise measurements that at the vibron energies of the molecule, a two-level fluctuation (TLF) is excited in the junction. Second, we show that in the presence of this TLF, a form of enhanced noise spectroscopy can be performed to detect inelastic electron-vibron interactions, by studying the third derivative of the noise (d3SI/dV3). This is possible because TLFs are insensitive to elastic scattering of electrons from defects, which nevertheless leave their signature in the usual inelastic electron tunnelling spectroscopy (IETS) measurements.
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Affiliation(s)
- Sumit Tewari
- Huygens-Kamerlingh Onnes Laboratory, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands.
| | - Carlos Sabater
- Huygens-Kamerlingh Onnes Laboratory, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands.
| | - Jan van Ruitenbeek
- Huygens-Kamerlingh Onnes Laboratory, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands.
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12
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Electronic noise due to temperature differences in atomic-scale junctions. Nature 2018; 562:240-244. [DOI: 10.1038/s41586-018-0592-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 08/20/2018] [Indexed: 11/08/2022]
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13
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Kosov DS. Telegraph noise in Markovian master equation for electron transport through molecular junctions. J Chem Phys 2018; 148:184108. [DOI: 10.1063/1.5033354] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Affiliation(s)
- Daniel S. Kosov
- College of Science and Engineering, James Cook University, Townsville, QLD 4811, Australia
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14
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Dependence of Stretch Length on Electrical Conductance and Electronic Structure of the Benzenedithiol Single Molecular Junction. E-JOURNAL OF SURFACE SCIENCE AND NANOTECHNOLOGY 2018. [DOI: 10.1380/ejssnt.2018.145] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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15
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Photochemical Reaction Using Aminobenzenethiol Single Molecular Junction. E-JOURNAL OF SURFACE SCIENCE AND NANOTECHNOLOGY 2018. [DOI: 10.1380/ejssnt.2018.137] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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16
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Magyarkuti A, Adak O, Halbritter A, Venkataraman L. Electronic and mechanical characteristics of stacked dimer molecular junctions. NANOSCALE 2018; 10:3362-3368. [PMID: 29388658 DOI: 10.1039/c7nr08354h] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Break-junction measurements are typically aimed at characterizing electronic properties of single molecules bound between two metal electrodes. Although these measurements have provided structure-function relationships for such devices, there is little work that studies the impact of molecule-molecule interactions on junction characteristics. Here, we use a scanning tunneling microscope based break-junction technique to study pi-stacked dimer junctions formed with two amine-terminated conjugated molecules. We show that the conductance, force and flicker noise of such dimers differ dramatically when compared with the corresponding monomer junctions and discuss the implications of these results on intra- and inter-molecular charge transport.
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Affiliation(s)
- András Magyarkuti
- Department of Physics, Budapest University of Technology and Economics and MTA-BME Condensed Matter Research Group, 1111 Budapest, Budafoki ut 8., Hungary.
| | - Olgun Adak
- Department of Applied Physics, Columbia University, New York, NY 10027, USA.
| | - Andras Halbritter
- Department of Physics, Budapest University of Technology and Economics and MTA-BME Condensed Matter Research Group, 1111 Budapest, Budafoki ut 8., Hungary.
| | - Latha Venkataraman
- Department of Applied Physics, Columbia University, New York, NY 10027, USA. and Department of Chemistry, Columbia University, New York, NY 10027, USA
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17
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KIGUCHI M. Studies on single-molecule bridging metal electrodes: development of new characterization technique and functionalities. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2018; 94:350-359. [PMID: 30416175 PMCID: PMC6275331 DOI: 10.2183/pjab.94.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 09/12/2018] [Indexed: 06/09/2023]
Abstract
A single molecular junction is a nanoscale structure prepared by bridging a single molecule between macroscopic metal electrodes. It has attracted significant attention due to its unique structure and potential applications in ultra-small single molecular electronic devices. It has two metal-molecule interfaces, and thus the electronic structure of the molecule can be significantly modulated from its original one. The single molecular junction can be regarded as a new material that includes metal electrodes, a so-called "double interface material". Therefore, we can expect unconventional physical and chemical properties. To develop a better understanding of the properties and functionalities of single molecular junctions, their atomic and electronic structures should be characterized. In this review, we describe the development of these characterization techniques, such as inelastic electron tunneling spectroscopy, surface-enhanced Raman scattering, as well as shot noise and thermopower measurements. We have also described some unique properties and functionalities of single molecular junctions, such as switching and diode properties.
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Affiliation(s)
- Manabu KIGUCHI
- Department of Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, Tokyo, Japan
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18
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Gu C, Wang H, Sun H, Liao J, Hou S, Guo X. Origin and mechanism analysis of asymmetric current fluctuations in single-molecule junctions. RSC Adv 2018; 8:39408-39413. [PMID: 35558058 PMCID: PMC9090728 DOI: 10.1039/c8ra08508k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 11/20/2018] [Indexed: 12/11/2022] Open
Abstract
The measurements of molecular electronic devices usually suffer from serious noise. Although noise hampers the operation of electric circuits in most cases, current fluctuations in single-molecule junctions are essentially related to their intrinsic quantum effects in the process of electron transport. Noise analysis can reveal and understand these processes from the behavior of current fluctuations. Here, in this study we observe and analyze the faint asymmetric current distribution in single-molecule junctions, in which the asymmetric intensity is highly related to the applied biases. The exploration of high-order moments within bias and temperature dependent measurements, in combination with model Hamiltonian calculations, statistically prove that the asymmetric current distribution originates from the inelastic electron tunneling process. Such results demonstrate a potential noise analysis method based on the fine structures of the current distribution rather than the noise power, which has obvious advantages in the investigation of the inelastic electron tunneling process in single-molecule junctions. The asymmetric current noise in a single-molecule device was observed, which is relevant to an inelastic electron transport process.![]()
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Affiliation(s)
- Chunhui Gu
- Beijing National Laboratory for Molecular Sciences
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species
- College of Chemistry and Molecular Engineering
- Peking University
- Beijing 100871
| | - Hao Wang
- Key Laboratory for the Physics and Chemistry of Nanodevices
- Department of Electronics
- Peking University
- Beijing 100871
- P. R. China
| | - Hantao Sun
- Key Laboratory for the Physics and Chemistry of Nanodevices
- Department of Electronics
- Peking University
- Beijing 100871
- P. R. China
| | - Jianhui Liao
- Key Laboratory for the Physics and Chemistry of Nanodevices
- Department of Electronics
- Peking University
- Beijing 100871
- P. R. China
| | - Shimin Hou
- Key Laboratory for the Physics and Chemistry of Nanodevices
- Department of Electronics
- Peking University
- Beijing 100871
- P. R. China
| | - Xuefeng Guo
- Beijing National Laboratory for Molecular Sciences
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species
- College of Chemistry and Molecular Engineering
- Peking University
- Beijing 100871
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19
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Towards Noise Simulation in Interacting Nonequilibrium Systems Strongly Coupled to Baths. Sci Rep 2017; 7:9735. [PMID: 28851909 PMCID: PMC5574948 DOI: 10.1038/s41598-017-09060-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 07/19/2017] [Indexed: 11/09/2022] Open
Abstract
Progress in experimental techniques at nanoscale makes measurements of noise in molecular junctions possible. These data are important source of information not accessible through average flux measurements. The emergence of optoelectronics, the recently shown possibility of strong light-matter couplings, and developments in the field of quantum thermodynamics are making measurements of transport statistics even more important. Theoretical methods for noise evaluation in first principles simulations can be roughly divided into approaches for weak intra-system interactions, and those treating strong interactions for systems weakly coupled to baths. We argue that due to structure of its diagrammatic expansion, and the use of many-body states as a basis of its formulation, the recently introduced nonequilibrium diagrammatic technique for Hubbard Green functions is a relatively inexpensive method suitable for evaluation of noise characteristics in first principles simulations over a wide range of parameters. We illustrate viability of the approach by simulations of noise and noise spectrum within generic models for non-, weakly and strongly interacting systems. Results of the simulations are compared to exact data (where available) and to simulations performed within approaches best suited for each of the three parameter regimes.
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20
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Magyarkuti A, Lauritzen KP, Balogh Z, Nyáry A, Mészáros G, Makk P, Solomon GC, Halbritter A. Temporal correlations and structural memory effects in break junction measurements. J Chem Phys 2017. [DOI: 10.1063/1.4975180] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- A. Magyarkuti
- Department of Physics, Budapest University of Technology and Economics, MTA-BME Condensed Matter Research Group, Budafoki ut 8, 1111 Budapest, Hungary
| | - K. P. Lauritzen
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Z. Balogh
- Department of Physics, Budapest University of Technology and Economics, MTA-BME Condensed Matter Research Group, Budafoki ut 8, 1111 Budapest, Hungary
| | - A. Nyáry
- Department of Physics, Budapest University of Technology and Economics, MTA-BME Condensed Matter Research Group, Budafoki ut 8, 1111 Budapest, Hungary
| | - G. Mészáros
- Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar Tudósok Körútja 2, H-1117 Budapest, Hungary
| | - P. Makk
- Department of Physics, Budapest University of Technology and Economics, MTA-BME Condensed Matter Research Group, Budafoki ut 8, 1111 Budapest, Hungary
| | - G. C. Solomon
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - A. Halbritter
- Department of Physics, Budapest University of Technology and Economics, MTA-BME Condensed Matter Research Group, Budafoki ut 8, 1111 Budapest, Hungary
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21
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Kosov DS. Waiting time distribution for electron transport in a molecular junction with electron-vibration interaction. J Chem Phys 2017; 146:074102. [PMID: 28228021 DOI: 10.1063/1.4976561] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Affiliation(s)
- Daniel S Kosov
- College of Science and Engineering, James Cook University, Townsville, QLD 4811, Australia
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22
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Kiguchi M, Fujii S. Governing the Metal–Molecule Interface: Towards New Functionality in Single-Molecule Junctions. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2017. [DOI: 10.1246/bcsj.20160229] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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23
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Galperin M. Photonics and spectroscopy in nanojunctions: a theoretical insight. Chem Soc Rev 2017; 46:4000-4019. [DOI: 10.1039/c7cs00067g] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Green function methods for photonics and spectroscopy in nanojunctions.
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Affiliation(s)
- Michael Galperin
- Department of Chemistry & Biochemistry
- University of California San Diego
- La Jolla
- USA
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24
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Rudge SL, Kosov DS. Distribution of residence times as a marker to distinguish different pathways for quantum transport. Phys Rev E 2016; 94:042134. [PMID: 27841516 DOI: 10.1103/physreve.94.042134] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Indexed: 11/07/2022]
Abstract
Electron transport through a nanoscale system is an inherently stochastic quantum mechanical process. Electric current is a time series of electron tunneling events separated by random intervals. Thermal and quantum noise are two sources of this randomness. In this paper we use the quantum master equation to consider the following questions. (i) Given that an electron has tunneled into the electronically unoccupied system from the source electrode at some particular time, how long is it until an electron tunnels out to the drain electrode to leave the system electronically unoccupied, where there are no intermediate tunneling events (the tunneling path)? (ii) Given that an electron tunneled into the unoccupied system from the source electrode at some particular time, how long is it until an electron tunnels out to the drain electrode to leave the system electronically unoccupied, where there are no intermediate tunneling events (a tunneling path)? (iii) What are the distributions of these times? We show that electron correlations suppress the difference between the electron tunneling path and an electron tunneling path.
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Affiliation(s)
- Samuel L Rudge
- College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia
| | - Daniel S Kosov
- College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia
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25
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Takahashi R, Kaneko S, Marqués-González S, Fujii S, Nishino T, Tsukagoshi K, Kiguchi M. Determination of the number of atoms present in nano contact based on shot noise measurements with highly stable nano-fabricated electrodes. NANOTECHNOLOGY 2016; 27:295203. [PMID: 27291763 DOI: 10.1088/0957-4484/27/29/295203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
A highly stable experimental setup was developed for the measurement of shot noise in atomic contacts and molecular junctions to determine the number of atoms or molecules present. The use of a nano-fabricated mechanically controllable break junction (MCBJ) electrode improved the overall stability of the experimental setup. The improved stability of the system and optimization of measurement system enabled us to comprehensively investigate the shot noise as well as charge transport properties in Au atomic contacts and molecular junctions. We present a solid proof that the number of atoms (cross sectional atom) in the Au atomic contacts was exactly one. In the atomic contacts, contribution from the additional channels was under the detection limit. Furthermore, the effect of molecular adsorption on the charge transport in the Au atomic contact was investigated. Additional transport channels were opened by exposing pyrazine molecules to the Au contacts, which gave rise to an increase in the Fano factor in the shot noise.
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Affiliation(s)
- Ryoji Takahashi
- Department of Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 W4-10, Ookayama, Meguro-ku, Tokyo 152-8551, Japan
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26
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Chen R, Natelson D. Evolution of shot noise in suspended lithographic gold break junctions with bias and temperature. NANOTECHNOLOGY 2016; 27:245201. [PMID: 27152886 DOI: 10.1088/0957-4484/27/24/245201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Shot noise is a powerful tool to probe correlations and microscopic transport details that conductance measurements alone cannot reveal. Even in atomic-scale Au devices that are well described by Landauer-Büttiker physics, complications remain such as local heating and electron-phonon interactions. We report systematic rf measurements of shot noise in individual atomic-scale gold break junctions at multiple temperatures, with most bias voltages well above the energy of the Au optical phonon mode. Motivated by the previous experimental evidence that electron-phonon interactions can modify Fano factors and result in kinked features in bias dependence of shot noise, we find that the temperature dependence of shot noise from 4.2 to 100 K is minimal. Enhanced Fano factors near [Formula: see text] and features beyond simply linear bias dependence of shot noise near the [Formula: see text] plateau are observed. Both are believed to have non-interacting origins and the latter likely results from slightly bias-dependent transmittance of the dominant quantum channel.
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Affiliation(s)
- Ruoyu Chen
- Department of Physics and Astronomy, Rice University, 6100 Main St., Houston, TX 77005, USA
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27
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Li Y, Demir F, Kaneko S, Fujii S, Nishino T, Saffarzadeh A, Kirczenow G, Kiguchi M. Electrical conductance and structure of copper atomic junctions in the presence of water molecules. Phys Chem Chem Phys 2016; 17:32436-42. [PMID: 26588589 DOI: 10.1039/c5cp05227k] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We have investigated Cu atomic contacts in the presence of H2O both experimentally and theoretically. The conductance measurements showed the formation of H2O/Cu junctions with a fixed conductance value of around 0.1 G0 (G0 = 2e(2)/h). These structures were found to be stable and could be stretched over 0.5 nm, indicating the formation of an atomic or molecular chain. In agreement with the experimental findings, theoretical calculations revealed that the conductance of H2O/Cu junctions decreases in stages as the junction is stretched, with the formation of a H2O/Cu atomic chain with a conductance of ca. 0.1 G0 prior to junction rupture. Conversely, in the absence of H2O, the conductance of the Cu junction remains close to 1 G0 prior to the junction rupture and abrupt conductance drop.
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Affiliation(s)
- Yu Li
- Department of Chemistry, Graduate School of Science and Engineering, Institute of Technology, 2-12-1 W4-10 Ookayama, Meguro-ku, Tokyo 152-8551, Japan.
| | - Firuz Demir
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6.
| | - Satoshi Kaneko
- Department of Chemistry, Graduate School of Science and Engineering, Institute of Technology, 2-12-1 W4-10 Ookayama, Meguro-ku, Tokyo 152-8551, Japan.
| | - Shintaro Fujii
- Department of Chemistry, Graduate School of Science and Engineering, Institute of Technology, 2-12-1 W4-10 Ookayama, Meguro-ku, Tokyo 152-8551, Japan.
| | - Tomoaki Nishino
- Department of Chemistry, Graduate School of Science and Engineering, Institute of Technology, 2-12-1 W4-10 Ookayama, Meguro-ku, Tokyo 152-8551, Japan.
| | - Alireza Saffarzadeh
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6. and Department of Physics, Payame Noor University, P.O. Box 19395-3697 Tehran, Iran
| | - George Kirczenow
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6.
| | - Manabu Kiguchi
- Department of Chemistry, Graduate School of Science and Engineering, Institute of Technology, 2-12-1 W4-10 Ookayama, Meguro-ku, Tokyo 152-8551, Japan.
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28
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Yi W, Savel'ev SE, Medeiros-Ribeiro G, Miao F, Zhang MX, Yang JJ, Bratkovsky AM, Williams RS. Quantized conductance coincides with state instability and excess noise in tantalum oxide memristors. Nat Commun 2016; 7:11142. [PMID: 27041485 PMCID: PMC4822004 DOI: 10.1038/ncomms11142] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 02/25/2016] [Indexed: 11/17/2022] Open
Abstract
Tantalum oxide memristors can switch continuously from a low-conductance semiconducting to a high-conductance metallic state. At the boundary between these two regimes are quantized conductance states, which indicate the formation of a point contact within the oxide characterized by multistable conductance fluctuations and enlarged electronic noise. Here, we observe diverse conductance-dependent noise spectra, including a transition from 1/f(2) (activated transport) to 1/f (flicker noise) as a function of the frequency f, and a large peak in the noise amplitude at the conductance quantum GQ=2e(2)/h, in contrast to suppressed noise at the conductance quantum observed in other systems. We model the stochastic behaviour near the point contact regime using Molecular Dynamics-Langevin simulations and understand the observed frequency-dependent noise behaviour in terms of thermally activated atomic-scale fluctuations that make and break a quantum conductance channel. These results provide insights into switching mechanisms and guidance to device operating ranges for different applications.
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Affiliation(s)
- Wei Yi
- Hewlett-Packard Laboratories, Palo Alto, California 94304, USA
- HRL Laboratories, LLC, Malibu, California 90265, USA
| | - Sergey E. Savel'ev
- Department of Physics, Loughborough University, Loughborough LE11 3TU, UK
| | - Gilberto Medeiros-Ribeiro
- Hewlett-Packard Laboratories, Palo Alto, California 94304, USA
- Departamento de Física, UFMG, PO Box 702, Belo Horizonte, 30123-970, Brazil
| | - Feng Miao
- Hewlett-Packard Laboratories, Palo Alto, California 94304, USA
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - M.-X. Zhang
- Hewlett-Packard Laboratories, Palo Alto, California 94304, USA
| | - J. Joshua Yang
- Hewlett-Packard Laboratories, Palo Alto, California 94304, USA
- Department of Electrical and Computer Engineering, University of Massachusetts, Amherst, Massachusetts 01003, USA
| | - Alexander M. Bratkovsky
- Hewlett-Packard Laboratories, Palo Alto, California 94304, USA
- Department of Physics, University of California, Davis, California 95616, USA
- P. L. Kapitza Institute for Physical Problems, 2 Kosygina Str., 119334 Moscow, Russia
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29
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Rudge SL, Kosov DS. Distribution of tunnelling times for quantum electron transport. J Chem Phys 2016; 144:124105. [PMID: 27036425 DOI: 10.1063/1.4944493] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
In electron transport, the tunnelling time is the time taken for an electron to tunnel out of a system after it has tunnelled in. We define the tunnelling time distribution for quantum processes in a dissipative environment and develop a practical approach for calculating it, where the environment is described by the general Markovian master equation. We illustrate the theory by using the rate equation to compute the tunnelling time distribution for electron transport through a molecular junction. The tunnelling time distribution is exponential, which indicates that Markovian quantum tunnelling is a Poissonian statistical process. The tunnelling time distribution is used not only to study the quantum statistics of tunnelling along the average electric current but also to analyse extreme quantum events where an electron jumps against the applied voltage bias. The average tunnelling time shows distinctly different temperature dependence for p- and n-type molecular junctions and therefore provides a sensitive tool to probe the alignment of molecular orbitals relative to the electrode Fermi energy.
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Affiliation(s)
- Samuel L Rudge
- College of Science, Technology and Engineering, James Cook University, Townsville, QLD 4811, Australia
| | - Daniel S Kosov
- College of Science, Technology and Engineering, James Cook University, Townsville, QLD 4811, Australia
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30
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Xiang D, Wang X, Jia C, Lee T, Guo X. Molecular-Scale Electronics: From Concept to Function. Chem Rev 2016; 116:4318-440. [DOI: 10.1021/acs.chemrev.5b00680] [Citation(s) in RCA: 816] [Impact Index Per Article: 102.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Dong Xiang
- Beijing
National Laboratory for Molecular Sciences, State Key Laboratory for
Structural Chemistry of Unstable and Stable Species, College of Chemistry
and Molecular Engineering, Peking University, Beijing 100871, China
- Key
Laboratory of Optical Information Science and Technology, Institute
of Modern Optics, College of Electronic Information and Optical Engineering, Nankai University, Tianjin 300071, China
| | - Xiaolong Wang
- Beijing
National Laboratory for Molecular Sciences, State Key Laboratory for
Structural Chemistry of Unstable and Stable Species, College of Chemistry
and Molecular Engineering, Peking University, Beijing 100871, China
| | - Chuancheng Jia
- Beijing
National Laboratory for Molecular Sciences, State Key Laboratory for
Structural Chemistry of Unstable and Stable Species, College of Chemistry
and Molecular Engineering, Peking University, Beijing 100871, China
| | - Takhee Lee
- Department
of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul 08826, Korea
| | - Xuefeng Guo
- Beijing
National Laboratory for Molecular Sciences, State Key Laboratory for
Structural Chemistry of Unstable and Stable Species, College of Chemistry
and Molecular Engineering, Peking University, Beijing 100871, China
- Department
of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China
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31
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Bâldea I. Invariance of molecular charge transport upon changes of extended molecule size and several related issues. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2016; 7:418-431. [PMID: 27335734 PMCID: PMC4901537 DOI: 10.3762/bjnano.7.37] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 02/24/2016] [Indexed: 06/06/2023]
Abstract
As a sanity test for the theoretical method employed, studies on (steady-state) charge transport through molecular devices usually confine themselves to check whether the method in question satisfies the charge conservation. Another important test of the theory's correctness is to check that the computed current does not depend on the choice of the central region (also referred to as the "extended molecule"). This work addresses this issue and demonstrates that the relevant transport and transport-related properties are indeed invariant upon changing the size of the extended molecule, when the embedded molecule can be described within a general single-particle picture (namely, a second-quantized Hamiltonian bilinear in the creation and annihilation operators). It is also demonstrates that the invariance of nonequilibrium properties is exhibited by the exact results but not by those computed approximately within ubiquitous wide- and flat-band limits (WBL and FBL, respectively). To exemplify the limitations of the latter, the phenomenon of negative differential resistance (NDR) is considered. It is shown that the exactly computed current may exhibit a substantial NDR, while the NDR effect is absent or drastically suppressed within the WBL and FBL approximations. The analysis done in conjunction with the WBLs and FBLs reveals why general studies on nonequilibrium properties require a more elaborate theoretical than studies on linear response properties (e.g., ohmic conductance and thermopower) at zero temperature. Furthermore, examples are presented that demonstrate that treating parts of electrodes adjacent to the embedded molecule and the remaining semi-infinite electrodes at different levels of theory (which is exactly what most NEGF-DFT approaches do) is a procedure that yields spurious structures in nonlinear ranges of current-voltage curves.
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Affiliation(s)
- Ioan Bâldea
- Theoretische Chemie, Universität Heidelberg, INF 229, 69120 Heidelberg, Germany
- Institute of Space Sciences, National Institute for Lasers, Plasma, and Radiation Physics, National Institute for Lasers, Plasma, and Radiation Physics, 077125, Bucharest-Măgurele, Romania
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32
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Karimi MA, Bahoosh SG, Herz M, Hayakawa R, Pauly F, Scheer E. Shot Noise of 1,4-Benzenedithiol Single-Molecule Junctions. NANO LETTERS 2016; 16:1803-1807. [PMID: 26859711 DOI: 10.1021/acs.nanolett.5b04848] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We report measurements of the shot noise on single-molecule Au-1,4-benzenedithiol-Au junctions, fabricated with the mechanically controllable break junction (MCBJ) technique at 4.2 K in a wide range of conductance values from 10(-2) to 0.24 conductance quanta. We introduce a simple measurement scheme using a current amplifier and a spectrum analyzer and that does not imply special requirements regarding the electrical leads. The experimental findings provide evidence that the current is carried by a single conduction channel throughout the whole conductance range. This observation suggests that the number of channels is limited by the Au-thiol bonds and that contributions due to direct tunneling from the Au to the π-system of the aromatic ring are negligible also for high conductance. The results are supported by quantum transport calculations using density functional theory.
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Affiliation(s)
- M A Karimi
- Department of Physics, University of Konstanz , 78457 Konstanz, Germany
| | - S G Bahoosh
- Department of Physics, University of Konstanz , 78457 Konstanz, Germany
| | - M Herz
- Department of Physics, University of Konstanz , 78457 Konstanz, Germany
| | - R Hayakawa
- Department of Physics, University of Konstanz , 78457 Konstanz, Germany
- International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science , 1-1 Namiki, Tsukuba 305-0044, Japan
| | - F Pauly
- Department of Physics, University of Konstanz , 78457 Konstanz, Germany
| | - E Scheer
- Department of Physics, University of Konstanz , 78457 Konstanz, Germany
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33
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Balogh Z, Makk P, Halbritter A. Alternative types of molecule-decorated atomic chains in Au-CO-Au single-molecule junctions. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2015; 6:1369-76. [PMID: 26199840 PMCID: PMC4505099 DOI: 10.3762/bjnano.6.141] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Accepted: 05/22/2015] [Indexed: 05/10/2023]
Abstract
We investigate the formation and evolution of Au-CO single-molecule break junctions. The conductance histogram exhibits two distinct molecular configurations, which are further investigated by a combined statistical analysis. According to conditional histogram and correlation analysis these molecular configurations show strong anticorrelations with each other and with pure Au monoatomic junctions and atomic chains. We identify molecular precursor configurations with somewhat higher conductance, which are formed prior to single-molecule junctions. According to detailed length analysis two distinct types of molecule-affected chain-formation processes are observed, and we compare these results to former theoretical calculations considering bridge- and atop-type molecular configurations where the latter has reduced conductance due to destructive Fano interference.
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Affiliation(s)
- Zoltán Balogh
- Department of Physics, Budapest University of Technology and Economics and MTA-BME Condensed Matter Research Group, Budafoki ut 8, 1111 Budapest, Hungary
| | - Péter Makk
- Department of Physics, Budapest University of Technology and Economics and MTA-BME Condensed Matter Research Group, Budafoki ut 8, 1111 Budapest, Hungary
| | - András Halbritter
- Department of Physics, Budapest University of Technology and Economics and MTA-BME Condensed Matter Research Group, Budafoki ut 8, 1111 Budapest, Hungary
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34
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Ochoa MA, Selzer Y, Peskin U, Galperin M. Pump-Probe Noise Spectroscopy of Molecular Junctions. J Phys Chem Lett 2015; 6:470-476. [PMID: 26261965 DOI: 10.1021/jz502484z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The slow response of electronic components in junctions limits the direct applicability of pump-probe type spectroscopy in assessing the intramolecular dynamics. Recently the possibility of getting information on a sub-picosecond time scale from dc current measurements was proposed. We revisit the idea of picosecond resolution by pump-probe spectroscopy from dc measurements and show that any intramolecular dynamics not directly related to charge transfer in the current direction is missed by current measurements. We propose a pump-probe dc shot noise spectroscopy as a suitable alternative. Numerical examples of time-dependent and average responses of junctions are presented for generic models.
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Affiliation(s)
| | - Yoram Selzer
- ‡School of Chemistry, Tel-Aviv University, Tel Aviv 69978, Israel
| | - Uri Peskin
- §Schulich Faculty of Chemistry and the Lise Meitner Center for Computational Quantum Chemistry, Technion - Israel Institute of Technology, Haifa 32000, Israel
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35
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Xiang D, Lee T, Kim Y, Mei T, Wang Q. Origin of discrete current fluctuations in a single molecule junction. NANOSCALE 2014; 6:13396-13401. [PMID: 25271483 DOI: 10.1039/c4nr03480e] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A series of fresh molecular junctions at a single molecule level were created and the current fluctuations were studied as electrons passed through them. Our results indicate that telegraph-like current fluctuations at room temperature neither originate from electron trapping/detrapping processes nor from molecule re-conformation. Our results will be helpful in better understanding the mechanism of current fluctuations.
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Affiliation(s)
- Dong Xiang
- School of Mathematics and Physics, China University of Geosciences, Wuhan 430074, China
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36
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Lu MP, Lu MY, Wang YJ. Low-frequency electrical fluctuations in metal-nanowire-metal phototransistors. NANOTECHNOLOGY 2014; 25:285202. [PMID: 24971527 DOI: 10.1088/0957-4484/25/28/285202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Using low-frequency noise spectroscopy to explore the physical origins of electrical fluctuations in ZnO nanowire (NW) phototransistors featuring a metal-NW-metal configuration, we have found that bulk mobility scatterings gave rise to electrical fluctuations in the low-gate voltage (V G) regime, providing values of Hooge's constant in the ranges 6.0-9.6 × 10(-3) and 1.9-2.2 × 10(-1) in the dark and under UV excitation, respectively. When moving into the higher V G regime, we assign the electrical fluctuations to an interaction process involving trapping and detrapping of channel carriers by charge traps located near the NW-dielectric interface, suggesting that the mechanism of the electrical fluctuation transitioned from bulk NW-dominated to NW/dielectric interface-dominated regimes. We have also addressed the effective density of interface traps responsible for the electrical fluctuations in the high-V G region. This report provides physical insight into the origins of electrical fluctuations in NW phototransistors.
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Affiliation(s)
- Ming-Pei Lu
- National Nano Device Laboratories, National Applied Research Laboratories, Hsinchu 300, Taiwan
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37
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Vardimon R, Yelin T, Klionsky M, Sarkar S, Biller A, Kronik L, Tal O. Probing the orbital origin of conductance oscillations in atomic chains. NANO LETTERS 2014; 14:2988-93. [PMID: 24810575 DOI: 10.1021/nl4041737] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We investigate periodical oscillations in the conductance of suspended Au and Pt atomic chains during elongation under mechanical stress. Analysis of conductance and shot noise measurements reveals that the oscillations are mainly related to variations in a specific conduction channel as the chain undergoes transitions between zigzag and linear atomic configurations. The calculated local electronic structure shows that the oscillations originate from varying degrees of hybridization between the atomic orbitals along the chain as a function of the zigzag angle. These variations are highly dependent on the directionally and symmetry of the relevant orbitals, in agreement with the order-of-magnitude difference between the Pt and Au oscillation amplitudes observed in experiment. Our results demonstrate that the sensitivity of conductance to structural variations can be controlled by designing atomic-scale conductors in view of the directional interactions between atomic orbitals.
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Affiliation(s)
- Ran Vardimon
- Department of Chemical Physics and ‡Department of Materials and Interfaces, Weizmann Institute of Science , Rehovot 76100, Israel
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38
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Sun L, Diaz-Fernandez YA, Gschneidtner TA, Westerlund F, Lara-Avila S, Moth-Poulsen K. Single-molecule electronics: from chemical design to functional devices. Chem Soc Rev 2014; 43:7378-411. [DOI: 10.1039/c4cs00143e] [Citation(s) in RCA: 361] [Impact Index Per Article: 36.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The use of single molecules in electronics represents the next limit of miniaturisation of electronic devices, which would enable to continue the trend of aggressive downscaling of silicon-based electronic devices.
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Affiliation(s)
- Lanlan Sun
- Department of Chemical and Biological Engineering
- Chalmers University of Technology
- , Sweden
| | - Yuri A. Diaz-Fernandez
- Department of Chemical and Biological Engineering
- Chalmers University of Technology
- , Sweden
| | - Tina A. Gschneidtner
- Department of Chemical and Biological Engineering
- Chalmers University of Technology
- , Sweden
| | - Fredrik Westerlund
- Department of Chemical and Biological Engineering
- Chalmers University of Technology
- , Sweden
| | - Samuel Lara-Avila
- Department of Micro and Nanotechnology
- MC2
- Chalmers University of Technology
- , Sweden
| | - Kasper Moth-Poulsen
- Department of Chemical and Biological Engineering
- Chalmers University of Technology
- , Sweden
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39
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Xiang D, Jeong H, Lee T, Mayer D. Mechanically controllable break junctions for molecular electronics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2013; 25:4845-67. [PMID: 23913697 DOI: 10.1002/adma.201301589] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Indexed: 05/13/2023]
Abstract
A mechanically controllable break junction (MCBJ) represents a fundamental technique for the investigation of molecular electronic junctions, especially for the study of the electronic properties of single molecules. With unique advantages, the MCBJ technique has provided substantial insight into charge transport processes in molecules. In this review, the techniques for sample fabrication, operation and the various applications of MCBJs are introduced and the history, challenges and future of MCBJs are discussed.
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Affiliation(s)
- Dong Xiang
- Department of Physics and Astronomy, Seoul National University, Gwanak-ro, Gwanak-gu, Seoul 151-747, Korea
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40
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Kaneko S, Motta C, Brivio GP, Kiguchi M. Mechanically controllable bi-stable states in a highly conductive single pyrazine molecular junction. NANOTECHNOLOGY 2013; 24:315201. [PMID: 23851468 DOI: 10.1088/0957-4484/24/31/315201] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We report the fabrication of a highly conductive single pyrazine molecular junction with Pt leads. Mechanically controllable break-junction measurements at low temperatures show two distinct high and low conductance states. These conductance values are two orders of magnitude larger than those of a conventional single molecular junction with anchoring groups because of direct binding of the π conjugated molecule to a metal electrode with large density of states at the Fermi energy. Inelastic electron tunneling spectroscopy combined with density functional theory calculations highlights the vibration modes of the system for the two regimes. Theory allows us to assign the high and low conductance states of the molecular junction to two configurations in which the pyrazine axis is tilted and parallel with respect to the junction axis, respectively. Finally, we show that the pyrazine junction can be reversibly switched between the two bi-stable conductance states by mechanically stretching and relaxing the junction.
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Affiliation(s)
- Satoshi Kaneko
- Department of Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo, Japan
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41
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Abstract
Single molecular junctions, in which a single molecule bridges between metal electrodes, have attracted wide attention as novel properties can appear due to their peculiar geometrical and electronic characters. The single molecular junction has also attracted attention due to its potential application in ultrasmall single molecular electronic devices, where single molecules are utilized as active electronic components. Thus, fabrication of single molecular junctions as well as understanding and controlling their properties (e.g. conductance, optical and magnetic properties) have become long-standing goals of scientists and engineers. This review article focuses on the experimental aspects of single molecular junctions, with primary focus on the electron transport mechanism.
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Affiliation(s)
- Manabu Kiguchi
- Department of Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 W4-10 Ookayama, Tokyo 152-8551, Japan.
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42
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Schneider NL, Lü JT, Brandbyge M, Berndt R. Light emission probing quantum shot noise and charge fluctuations at a biased molecular junction. PHYSICAL REVIEW LETTERS 2012; 109:186601. [PMID: 23215305 DOI: 10.1103/physrevlett.109.186601] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Indexed: 06/01/2023]
Abstract
The emission of plasmonic light from a single C(60) molecule on Cu(111) is probed in a scanning tunneling microscope from the weak-coupling, tunneling range to strong coupling of the molecule to the electrodes at contact. At positive sample voltage the photon yield decreases owing to shot-noise suppression in an increasingly transparent quantum contact. At reversed bias an unexpected nonlinear increase occurs. First-principles transport calculations reveal that ultrafast charge fluctuations on the molecule give rise to additional noise at optical frequencies beyond the shot noise of the current that is injected to the tip.
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Affiliation(s)
- N L Schneider
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, D-24098 Kiel, Germany
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43
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Koleini M, Brandbyge M. Strong spin-filtering and spin-valve effects in a molecular V-C(60)-V contact. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2012; 3:589-96. [PMID: 23019556 PMCID: PMC3458606 DOI: 10.3762/bjnano.3.69] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Accepted: 07/20/2012] [Indexed: 06/01/2023]
Abstract
Motivated by the recent achievements in the manipulation of C(60) molecules in STM experiments, we study theoretically the structure and electronic properties of a C(60) molecule in an STM tunneljunction with a magnetic tip and magnetic adatom on a Cu(111) surface using first-principles calculations. For the case of a vanadium tip/adatom, we demonstrate how spin coupling between the magnetic V atoms, mediated by the C(60), can be observed in the electronic transport, which display a strong spin-filtering effect, allowing mainly majority-spin electrons to pass (>95%). Moreover, we find a significant change in the conductance between parallel and anti-parallel spin polarizations in the junction (86%) which suggests that STM experiments should be able to characterize the magnetism and spin coupling for these systems.
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Affiliation(s)
- Mohammad Koleini
- Hybrid Materials Interfaces Group, Faculty of Production Engineering and Bremen Center for Computational Materials Science, University of Bremen, 28359 Bremen, Germany
| | - Mads Brandbyge
- DTU Nanotech, Department of Micro and Nanotechnology, Technical University of Denmark, Ørsteds Plads, Building 345E, DK-2800 Kongens Lyngby, Denmark
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44
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Makk P, Balogh Z, Csonka S, Halbritter A. Pulling platinum atomic chains by carbon monoxide molecules. NANOSCALE 2012; 4:4739-45. [PMID: 22751796 DOI: 10.1039/c2nr30832k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The interaction of carbon monoxide molecules with atomic-scale platinum nanojunctions is investigated by low temperature mechanically controllable break junction experiments. Combining plateau length analysis, two-dimensional conductance-displacement histograms and conditional correlation analysis a comprehensive microscopic picture is proposed about the formation and evolution of Pt-CO-Pt single-molecule configurations. Our analysis implies that before pure Pt monoatomic chains are formed a CO molecule infiltrates the junction, first in a configuration that is perpendicular to the contact axis. This molecular junction is strong enough to pull a monoatomic platinum chain with the molecule being incorporated in the chain. Along the chain formation the molecule can either stay in the perpendicular configuration, or rotate to a parallel configuration. The evolution of the single-molecule configurations along the junction displacement shows quantitative agreement with theoretical predictions, justifying the interpretation in terms of perpendicular and parallel molecular alignment. Our analysis demonstrates that the combination of two-dimensional conductance-displacement histograms with conditional correlation analysis is a useful tool to analyze separately fundamentally different types of junction trajectories in single molecule break junction experiments.
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Affiliation(s)
- P Makk
- Department of Physics, Budapest University of Technology and Economics and Condensed Matter Research Group of the Hungarian Academy of Sciences, Budafoki ut 8, 1111 Budapest, Hungary
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45
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Natelson D. Mechanical break junctions: enormous information in a nanoscale package. ACS NANO 2012; 6:2871-2876. [PMID: 22483036 DOI: 10.1021/nn301323u] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Mechanical break junctions, particularly those in which a metal tip is repeatedly moved in and out of contact with a metal film, have provided many insights into electronic conduction at the atomic and molecular scale, most often by averaging over many possible junction configurations. This averaging throws away a great deal of information, and Makk et al. in this issue of ACS Nano demonstrate that, with both simulated and real experimental data, more sophisticated two-dimensional analysis methods can reveal information otherwise obscured in simple histograms. As additional measured quantities come into play in break junction experiments, including thermopower, noise, and optical response, these more sophisticated analytic approaches are likely to become even more powerful. While break junctions are not directly practical for useful electronic devices, they are incredibly valuable tools for unraveling the electronic transport physics relevant for ultrascaled nanoelectronics.
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Affiliation(s)
- Douglas Natelson
- Department of Physics and Astronomy, Rice University, 6100 Main Street, Houston, Texas 77005, United States.
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46
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Kumar M, Avriller R, Yeyati AL, van Ruitenbeek JM. Detection of vibration-mode scattering in electronic shot noise. PHYSICAL REVIEW LETTERS 2012; 108:146602. [PMID: 22540815 DOI: 10.1103/physrevlett.108.146602] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Indexed: 05/31/2023]
Abstract
We present shot noise measurements on Au nanowires showing very pronounced vibration-mode features. In accordance to recent theoretical predictions the sign of the inelastic signal, i.e., the signal due to vibration excitations, depends on the transmission probability becoming negative below a certain transmission value. We argue that the negative contribution to noise arises from coherent two-electron processes mediated by electron-phonon scattering and the Pauli exclusion principle. These signals can provide unique information on the local phonon population and lattice temperature of the nanoscale system.
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Affiliation(s)
- Manohar Kumar
- Kamerlingh Onnes Laboratorium, Universiteit Leiden, PO Box 9504, 2300 RA Leiden, The Netherlands
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47
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Kiguchi M, Kaneko S. Electron transport through single π-conjugated molecules bridging between metal electrodes. Chemphyschem 2012; 13:1116-26. [PMID: 22311828 DOI: 10.1002/cphc.201100772] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2011] [Indexed: 11/06/2022]
Abstract
Understanding electron transport through a single molecule bridging between metal electrodes is a central issue in the field of molecular electronics. This review covers the fabrication and electron-transport properties of single π-conjugated molecule junctions, which include benzene, fullerene, and π-stacked molecules. The metal/molecule interface plays a decisive role in determining the stability and conductivity of single-molecule junctions. The effect of the metal-molecule contact on the conductance of the single π-conjugated molecule junction is reviewed. The characterization of the single benzene molecule junction is also discussed using inelastic electron tunneling spectroscopy and shot noise. Finally, electron transport through the π-stacked system using π-stacked aromatic molecules enclosed within self-assembled coordination cages is reviewed. The electron transport in the π-stacked systems is found to be efficient at the single-molecule level, thus providing insight into the design of conductive materials.
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Affiliation(s)
- Manabu Kiguchi
- Department of Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 W4-10 Ookayama, Meguro-ku, Tokyo 152-8551, Japan.
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48
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Bergfield JP, Barr JD, Stafford CA. Transmission eigenvalue distributions in highly conductive molecular junctions. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2012; 3:40-51. [PMID: 22428095 PMCID: PMC3304317 DOI: 10.3762/bjnano.3.5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Accepted: 12/01/2011] [Indexed: 05/23/2023]
Abstract
BACKGROUND The transport through a quantum-scale device may be uniquely characterized by its transmission eigenvalues τ(n). Recently, highly conductive single-molecule junctions (SMJ) with multiple transport channels (i.e., several τ(n) > 0) have been formed from benzene molecules between Pt electrodes. Transport through these multichannel SMJs is a probe of both the bonding properties at the lead-molecule interface and of the molecular symmetry. RESULTS We use a many-body theory that properly describes the complementary wave-particle nature of the electron to investigate transport in an ensemble of Pt-benzene-Pt junctions. We utilize an effective-field theory of interacting π-electrons to accurately model the electrostatic influence of the leads, and we develop an ab initio tunneling model to describe the details of the lead-molecule bonding over an ensemble of junction geometries. We also develop a simple decomposition of transmission eigenchannels into molecular resonances based on the isolated resonance approximation, which helps to illustrate the workings of our many-body theory, and facilitates unambiguous interpretation of transmission spectra. CONCLUSION We confirm that Pt-benzene-Pt junctions have two dominant transmission channels, with only a small contribution from a third channel with τ(n) << 1. In addition, we demonstrate that the isolated resonance approximation is extremely accurate and determine that transport occurs predominantly via the HOMO orbital in Pt-benzene-Pt junctions. Finally, we show that the transport occurs in a lead-molecule coupling regime where the charge carriers are both particle-like and wave-like simultaneously, requiring a many-body description.
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Affiliation(s)
- Justin P Bergfield
- Departments of Chemistry and Physics, University of California, Irvine, California 92697, USA
| | - Joshua D Barr
- Department of Physics, University of Arizona, 1118 East Fourth Street, Tucson, AZ 85721, USA
| | - Charles A Stafford
- Department of Physics, University of Arizona, 1118 East Fourth Street, Tucson, AZ 85721, USA
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49
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Makk P, Visontai D, Oroszlány L, Manrique DZ, Csonka S, Cserti J, Lambert C, Halbritter A. Advanced simulation of conductance histograms validated through channel-sensitive experiments on indium nanojunctions. PHYSICAL REVIEW LETTERS 2011; 107:276801. [PMID: 22243322 DOI: 10.1103/physrevlett.107.276801] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Indexed: 05/31/2023]
Abstract
We demonstrate a self-contained methodology for predicting conductance histograms of atomic and molecular junctions. Fast classical molecular-dynamics simulations are combined with accurate density functional theory calculations predicting both quantum transport properties and molecular-dynamics force field parameters. The methodology is confronted with experiments on atomic-sized indium nanojunctions. Beside conductance histograms the distribution of individual channel transmission eigenvalues is also determined by fitting the superconducting subgap features in the I-V curves. The remarkable agreement in the evolution of the channel transmissions demonstrates that the simulated ruptures are able to reproduce a realistic statistical ensemble of contact configurations, whereas simulations on selected ideal geometries show strong deviations from the experimental observations.
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Affiliation(s)
- P Makk
- Department of Physics, Budapest University of Technology, Budapest, Hungary
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50
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Bergfield JP, Barr JD, Stafford CA. The number of transmission channels through a single-molecule junction. ACS NANO 2011; 5:2707-2714. [PMID: 21417212 DOI: 10.1021/nn1030753] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We calculate transmission eigenvalue distributions for Pt-benzene-Pt and Pt-butadiene-Pt junctions using realistic state-of-the-art many-body techniques. An effective field theory of interacting π-electrons is used to include screening and van der Waals interactions with the metal electrodes. We find that the number of dominant transmission channels in a molecular junction is equal to the degeneracy of the molecular orbital closest to the metal Fermi level.
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Affiliation(s)
- Justin P Bergfield
- College of Optical Sciences, University of Arizona, 1630 East University Boulevard, Arizona 85721, USA
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