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Kershaw VF, Kosov DS. Non-adiabatic effects of nuclear motion in quantum transport of electrons: A self-consistent Keldysh-Langevin study. J Chem Phys 2020; 153:154101. [PMID: 33092389 DOI: 10.1063/5.0023275] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The molecular junction geometry is modeled in terms of nuclear degrees of freedom that are embedded in a stochastic quantum environment of non-equilibrium electrons. The time-evolution of the molecular geometry is governed via a mean force, a frictional force, and a stochastic force, forces arising from many electrons tunneling across the junction for a given nuclear vibration. Conversely, the current-driven nuclear dynamics feed back to the electronic current, which can be captured according to the extended expressions for the current that have explicit dependences on classical nuclear velocities and accelerations. Current-induced nuclear forces and the non-adiabatic electric current are computed using non-equilibrium Green's functions via a timescale separation solution of Keldysh-Kadanoff-Baym equations in the Wigner space. Applying the theory to molecular junctions demonstrated that non-adiabatic corrections play an important role when nuclear motion is considered non-equilibrium and, in particular, showed that non-equilibrium and equilibrium descriptions of nuclear motion produce significantly different current characteristics. It is observed that non-equilibrium descriptions generally produce heightened conductance profiles relative to the equilibrium descriptions and provide evidence that the effective temperature is an effective measure of the steady-state characteristics. Finally, we observe that the non-equilibrium descriptions of nuclear motion can give rise to the Landauer blowtorch effect via the emergence of multi-minima potential energy surfaces in conjunction with non-uniform temperature profiles. The Landauer blowtorch effect and its impact on the current characteristics, waiting times, and the Fano factor are explored for an effective adiabatic potential that morphs between a single, double, and triple potential as a function of voltage.
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Affiliation(s)
- Vincent F Kershaw
- College of Science and Engineering, James Cook University, Townsville, QLD 4811, Australia
| | - Daniel S Kosov
- College of Science and Engineering, James Cook University, Townsville, QLD 4811, Australia
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2
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Pickup BT, Fowler PW. A Correlated Source-Sink-Potential Model Consistent with the Meir–Wingreen Formula. J Phys Chem A 2020; 124:6928-6944. [DOI: 10.1021/acs.jpca.0c01711] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Barry T. Pickup
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, UK
| | - Patrick W. Fowler
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, UK
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3
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Xu Y, Wang M, Fang C, Cui B, Ji G, Zhao W, Liu D, Wang C, Qin M. Lateral scaling and positioning effects of top-gate electrodes on single-molecule field-effect transistors. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:285302. [PMID: 30952153 DOI: 10.1088/1361-648x/ab1680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Molecular electronics aims at integrating controllable molecular devices into circuits or machines to realize certain functions. According to device configuration, molecular field-effect transistors with top-gate electrodes have great advantages for integration. Nevertheless, from technical aspects, it is difficult to control lateral scale and position of a top-gate electrode precisely. Therefore, one problem arises in how lateral scaling and positioning effects of a top-gate electrode affect device performance. To solve this problem, the electronic transport properties of single-molecule field-effect transistor configurations modulated by a series of partial-scale top-gate electrodes with different lateral scales and positions are studied by using non-equilibrium Green's function in combination with density functional theory, and compared with those of the full gate electrode (can be considered as a bottom gate electrode). The results show that lateral scaling and positioning effects indeed have a great impact on electronic transport properties of single-molecule field-effect transistor configurations. For [Formula: see text]-saturated 1,12-dodecanedithiol devices, larger lateral scale of a partial-scale top-gate electrode obtains larger amplification coefficient [Formula: see text] (ratio of device conductances with/without a gate electrode), and even larger [Formula: see text] than that of the full gate electrode. While lateral positioning effect has little influence on this device. For [Formula: see text]-conjugated 1,3,5,7,9,11-dodehexaene-1,12-dithiol devices, performance of a partial-scale top-gate electrode mainly depends on locations of its two edges, i.e. the number of [Formula: see text] bonds that it breaks. These results will provide theoretical directions in device designing and manufacturing in the future.
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Affiliation(s)
- Yuqing Xu
- School of Physics and Optoelectronic Engineering, Ludong University, Yantai 264025, People's Republic of China
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Cuny J, Tarrat N, Spiegelman F, Huguenot A, Rapacioli M. Density-functional tight-binding approach for metal clusters, nanoparticles, surfaces and bulk: application to silver and gold. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:303001. [PMID: 29916820 DOI: 10.1088/1361-648x/aacd6c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Density-functional based tight-binding (DFTB) is an efficient quantum mechanical method that can describe a variety of systems, going from organic and inorganic compounds to metallic and hybrid materials. The present topical review addresses the ability and performance of DFTB to investigate energetic, structural, spectroscopic and dynamical properties of gold and silver materials. After a brief overview of the theoretical basis of DFTB, its parametrization and its transferability, we report its past and recent applications to gold and silver systems, including small clusters, nanoparticles, bulk and surfaces, bare and interacting with various organic and inorganic compounds. The range of applications covered by those studies goes from plasmonics and molecular electronics, to energy conversion and surface chemistry. Finally, perspectives of DFTB in the field of gold and silver surfaces and NPs are outlined.
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Affiliation(s)
- Jérôme Cuny
- Laboratoire de Chimie et Physique Quantiques (LCPQ), Université de Toulouse III [UPS] and CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
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5
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Thoss M, Evers F. Perspective: Theory of quantum transport in molecular junctions. J Chem Phys 2018; 148:030901. [DOI: 10.1063/1.5003306] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Michael Thoss
- Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, D-79104 Freiburg, Germany
| | - Ferdinand Evers
- Institute of Theoretical Physics, University of Regensburg, Universitätsstr. 31, D-93053 Regensburg, Germany
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Abstract
David Craig (1919–2015) left us with a lasting legacy concerning basic understanding of chemical spectroscopy and bonding. This is expressed in terms of some of the recent achievements of my own research career, with a focus on integration of Craig’s theories with those of Noel Hush to solve fundamental problems in photosynthesis, molecular electronics (particularly in regard to the molecules synthesized by Maxwell Crossley), and self-assembled monolayer structure and function. Reviewed in particular is the relation of Craig’s legacy to: the 50-year struggle to assign the visible absorption spectrum of arguably the world’s most significant chromophore, chlorophyll; general theories for chemical bonding and structure extending Hush’s adiabatic theory of electron-transfer processes; inelastic electron-tunnelling spectroscopy (IETS); chemical quantum entanglement and the Penrose–Hameroff model for quantum consciousness; synthetic design strategies for NMR quantum computing; Gibbs free-energy measurements and calculations for formation and polymorphism of organic self-assembled monolayers on graphite surfaces from organic solution; and understanding the basic chemical processes involved in the formation of gold surfaces and nanoparticles protected by sulfur-bound ligands, ligands whose form is that of Au0-thiyl rather than its commonly believed AuI-thiolate tautomer.
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Schwarz F, Lörtscher E. Break-junctions for investigating transport at the molecular scale. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:474201. [PMID: 25352355 DOI: 10.1088/0953-8984/26/47/474201] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Break-junctions (BJs) enable a pair of atomic-sized electrodes to be created and the relative position between them to be controlled with sub-nanometer accuracy by mechanical means-a level of microscopic control that is not yet achievable by top-down fabrication. Locally, a BJ consists of a single-atom contact, an arrangement that is ideal not only to study various types of quantum point contacts, but also to investigate transport through an individual molecule that can bridge such a junction. In this topical review, we will provide a broad overview on the field of single-molecule electronics, in which BJs serve as the main tool of investigation. To correlate the molecular structure and transport properties to gain a fundamental understanding of the underlying transport mechanisms at the molecular scale, basic experiments that systematically cover all aspects of transport by rational chemical design and tailored experiments are needed. The variety of fascinating transport mechanisms and intrinsic molecular functionalities discovered in the past range from nonlinear transport over conductance switching to quantum interference effects observable even at room temperature. Beside discussing these results, we also look at novel directions and the most recent advances in molecular electronics investigating simultaneously electronic transport and also the mechanical and thermal properties of single-molecule junctions as well as the interaction between molecules and light. Finally, we will describe the requirements for a stepwise transition from fundamental BJ experiments towards technology-relevant architectures for future nanoelectronics applications based on ultimately-scaled molecular building blocks.
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Affiliation(s)
- Florian Schwarz
- IBM Research-Zurich, Department of Science and Technology, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
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Lykkebo J, Gagliardi A, Pecchia A, Solomon GC. Strong overtones modes in inelastic electron tunneling spectroscopy with cross-conjugated molecules: a prediction from theory. ACS NANO 2013; 7:9183-94. [PMID: 24067128 PMCID: PMC3807527 DOI: 10.1021/nn4037915] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 09/19/2013] [Indexed: 05/31/2023]
Abstract
Cross-conjugated molecules are known to exhibit destructive quantum interference, a property that has recently received considerable attention in single-molecule electronics. Destructive quantum interference can be understood as an antiresonance in the elastic transmission near the Fermi energy and leading to suppressed levels of elastic current. In most theoretical studies, only the elastic contributions to the current are taken into account. In this paper, we study the inelastic contributions to the current in cross-conjugated molecules and find that while the inelastic contribution to the current is larger than for molecules without interference, the overall behavior of the molecule is still dominated by the quantum interference feature. Second, an ongoing challenge for single molecule electronics is understanding and controlling the local geometry at the molecule-surface interface. With this in mind, we investigate a spectroscopic method capable of providing insight into these junctions for cross-conjugated molecules: inelastic electron tunneling spectroscopy (IETS). IETS has the advantage that the molecule interface is probed directly by the tunneling current. Previously, it has been thought that overtones are not observable in IETS. Here, overtones are predicted to be strong and, in some cases, the dominant spectroscopic features. We study the origin of the overtones and find that the interference features in these molecules are the key ingredient. The interference feature is a property of the transmission channels of the π system only, and consequently, in the vicinity of the interference feature, the transmission channels of the σ system and the π system become equally transmissive. This allows for scattering between the different transmission channels, which serves as a pathway to bypass the interference feature. A simple model calculation is able to reproduce the results obtained from atomistic calculations, and we use this to interpret these findings.
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Affiliation(s)
- Jacob Lykkebo
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
| | - Alessio Gagliardi
- Department of Electronic Engineering, Università di Roma “Tor Vergata”, Via del Politecnico 1, 00133 Rome, Italy
| | - Alessandro Pecchia
- Consiglio Nazionale delle Ricerche, ISMN, Via Salaria km 29.6, 00017 Monterotondo, Rome, Italy
| | - Gemma C. Solomon
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
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Solomon GC, Bergfield JP, Stafford CA, Ratner MA. When "small" terms matter: Coupled interference features in the transport properties of cross-conjugated molecules. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2011; 2:862-71. [PMID: 22259770 PMCID: PMC3257512 DOI: 10.3762/bjnano.2.95] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 11/25/2011] [Indexed: 05/23/2023]
Abstract
Quantum interference effects offer opportunities to tune the electronic and thermoelectric response of a quantum-scale device over orders of magnitude. Here we focus on single-molecule devices, in which interference features may be strongly affected by both chemical and electronic modifications to the system. Although not always desirable, such a susceptibility offers insight into the importance of "small" terms, such as through-space coupling and many-body charge-charge correlations. Here we investigate the effect of these small terms using different Hamiltonian models with Hückel, gDFTB and many-body theory to calculate the transport through several single-molecule junctions, finding that terms that are generally thought to only slightly perturb the transport instead produce significant qualitative changes in the transport properties. In particular, we show that coupling of multiple interference features in cross-conjugated molecules by through-space coupling will lead to splitting of the features, as can correlation effects. The degeneracy of multiple interference features in cross-conjugated molecules appears to be significantly more sensitive to perturbations than those observed in equivalent cyclic systems and this needs to be considered if such supernodes are required for molecular thermoelectric devices.
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Affiliation(s)
- Gemma C Solomon
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
| | - Justin P Bergfield
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
| | - Charles A Stafford
- Department of Physics, University of Arizona, 1118 East Fourth Street, Tucson, AZ 85721, USA
| | - Mark A Ratner
- Department of Chemistry, Northwestern University, 2145 Sheridan Rd, Evanston, IL 60208, USA
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Lörtscher E. The Role of Symmetry in Single-Molecule Junctions. Chemphyschem 2011; 12:2887-9. [DOI: 10.1002/cphc.201100702] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Indexed: 11/11/2022]
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11
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Perrine TM, Dunietz BD. Contact Geometry Symmetry Dependence of Field Effect Gating in Single-Molecule Transistors. J Am Chem Soc 2010; 132:2914-8. [DOI: 10.1021/ja906234v] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Trilisa M. Perrine
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109
| | - Barry D. Dunietz
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109
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12
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Exploring local currents in molecular junctions. Nat Chem 2010; 2:223-8. [DOI: 10.1038/nchem.546] [Citation(s) in RCA: 335] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Accepted: 12/23/2009] [Indexed: 12/25/2022]
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13
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Solomon GC, Andrews DQ, Van Duyne RP, Ratner MA. Electron Transport through Conjugated Molecules: When the π System Only Tells Part of the Story. Chemphyschem 2009; 10:257-64. [DOI: 10.1002/cphc.200800591] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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14
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Goker A, Goyer F, Ernzerhof M. Bond dissociation and correlation effects in molecular electronic devices. J Chem Phys 2008; 129:194901. [DOI: 10.1063/1.3013815] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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15
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Perrine TM, Berto T, Dunietz BD. Enhanced Conductance via Induced Π-Stacking Interactions in Cobalt(II) Terpyridine Bridged Complexes. J Phys Chem B 2008; 112:16070-5. [DOI: 10.1021/jp8075854] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Timothy Berto
- The University of Michigan, Ann Arbor, Michigan 48109
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Troisi A. Inelastic electron tunnelling in saturated molecules with different functional groups: correlations and symmetry considerations from a computational study. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2008; 20:374111. [PMID: 21694418 DOI: 10.1088/0953-8984/20/37/374111] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The inelastic electron tunnelling (IET) spectra of a series of molecules with the commonest functional groups are evaluated computationally. It is found that ether, secondary amine and thioether groups do not leave any characteristic signatures on the IET spectrum (in comparison with simple alkanes) and they cannot be used as 'tracers' for the tunnelling path of the electron. In contrast, carbonyl and ester groups modify the appearance of the IET spectrum considerably. The series of computations was also used to validate, for the case of saturated molecules, the propensity rules for IET spectroscopy proposed in the literature. It is found that totally symmetric vibrations give the largest contribution to the spectrum and that there is no correlation between IET and infrared or Raman absorption intensities.
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Affiliation(s)
- Alessandro Troisi
- Department of Chemistry and Centre of Scientific Computing, University of Warwick, Coventry CV4 7AL, UK
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Zhang J, Kuznetsov AM, Medvedev IG, Chi Q, Albrecht T, Jensen PS, Ulstrup J. Single-Molecule Electron Transfer in Electrochemical Environments. Chem Rev 2008; 108:2737-91. [PMID: 18620372 DOI: 10.1021/cr068073+] [Citation(s) in RCA: 252] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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18
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Solomon GC, Andrews DQ, Van Duyne RP, Ratner MA. When Things Are Not as They Seem: Quantum Interference Turns Molecular Electron Transfer “Rules” Upside Down. J Am Chem Soc 2008; 130:7788-9. [DOI: 10.1021/ja801379b] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Gemma C. Solomon
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208
| | - David Q. Andrews
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208
| | | | - Mark A. Ratner
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208
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Perrine TM, Smith RG, Marsh C, Dunietz BD. Gating of single molecule transistors: Combining field-effect and chemical control. J Chem Phys 2008; 128:154706. [DOI: 10.1063/1.2897425] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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20
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Wohlthat S, Pauly F, Reimers JR. The conduction properties of α,ω-diaminoalkanes and hydrazine bridging gold electrodes. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2008.02.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Reimers JR, Solomon GC, Gagliardi A, Bilić A, Hush NS, Frauenheim T, Di Carlo A, Pecchia A. The Green's Function Density Functional Tight-Binding (gDFTB) Method for Molecular Electronic Conduction. J Phys Chem A 2007; 111:5692-702. [PMID: 17530826 DOI: 10.1021/jp070598y] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A review is presented of the nonequilibrium Green's function (NEGF) method "gDFTB" for evaluating elastic and inelastic conduction through single molecules employing the density functional tight-binding (DFTB) electronic structure method. This focuses on the possible advantages that DFTB implementations of NEGF have over conventional methods based on density functional theory, including not only the ability to treat large irregular metal-molecule junctions with high nonequilibrium thermal distributions but perhaps also the ability to treat dispersive forces, bond breakage, and open-shell systems and to avoid large band lineup errors. New results are presented indicating that DFTB provides a useful depiction of simple gold-thiol interactions. Symmetry is implemented in DFTB, and the advantages it brings in terms of large savings of computational resources with significant increase in numerical stability are described. The power of DFTB is then harnessed to allow the use of gDFTB as a real-time tool to discover the nature of the forces that control inelastic charge transport through molecules and the role of molecular symmetry in determining both elastic and inelastic transport. Future directions for the development of the method are discussed.
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Goyer F, Ernzerhof M, Zhuang M. Source and sink potentials for the description of open systems with a stationary current passing through. J Chem Phys 2007; 126:144104. [PMID: 17444698 DOI: 10.1063/1.2715932] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The authors present a model Hamiltonian for the description of open systems that exchange probability current density with their surroundings. The complex potentials appearing in this Hamiltonian act as source and sink, respectively, of probability current density. The primary applications of the theory of source and sink potentials are molecular electronic devices (MEDs), in the description of which the semi-infinite contacts are replaced by complex potentials. This is done in a rigorous manner, i.e., the exact wave function is recovered in the interior of the MED. To illustrate the approach, certain prototypical molecular conductors are considered in the Huckel approximation. The authors show that, for the examples considered, there exist almost isolated molecular states in the continuum of contact states that manifest themselves as Fano resonances in the transmission probability. The findings are confirmed by density functional theory calculations that also yield the predicted molecular states that are nearly decoupled from the contacts.
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Affiliation(s)
- Francois Goyer
- Départment de Chimie, Université de Montréal, C.P. 6128 Succursale A, Montréal, Québec H3C 3J7, Canada
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