Transition voltages of vacuum-spaced and molecular junctions with Ag and Pt electrodes

Handle URI:
http://hdl.handle.net/10754/600066
Title:
Transition voltages of vacuum-spaced and molecular junctions with Ag and Pt electrodes
Authors:
Wu, Kunlin; Bai, Meilin; Sanvito, Stefano; Hou, Shimin
Abstract:
The transition voltage of vacuum-spaced and molecular junctions constructed with Ag and Pt electrodes is investigated by non-equilibrium Green's function formalism combined with density functional theory. Our calculations show that, similarly to the case of Au-vacuum-Au previously studied, the transition voltages of Ag and Pt metal-vacuum-metal junctions with atomic protrusions on the electrode surface are determined by the local density of states of the p-type atomic orbitals of the protrusion. Since the energy position of the Pt 6p atomic orbitals is higher than that of the 5p/6p of Ag and Au, the transition voltage of Pt-vacuum-Pt junctions is larger than that of both Ag-vacuum-Ag and Au-vacuum-Au junctions. When one moves to analyzing asymmetric molecular junctions constructed with biphenyl thiol as central molecule, then the transition voltage is found to depend on the specific bonding site for the sulfur atom in the thiol group. In particular agreement with experiments, where the largest transition voltage is found for Ag and the smallest for Pt, is obtained when one assumes S binding at the hollow-bridge site on the Ag/Au(111) surface and at the adatom site on the Pt(111) one. This demonstrates the critical role played by the linker-electrode binding geometry in determining the transition voltage of devices made of conjugated thiol molecules. © 2014 AIP Publishing LLC.
Citation:
Wu K, Bai M, Sanvito S, Hou S (2014) Transition voltages of vacuum-spaced and molecular junctions with Ag and Pt electrodes. J Chem Phys 141: 014707. Available: http://dx.doi.org/10.1063/1.4886378.
Publisher:
AIP Publishing
Journal:
The Journal of Chemical Physics
KAUST Grant Number:
FIC/2010/08
Issue Date:
7-Jul-2014
DOI:
10.1063/1.4886378
PubMed ID:
25005303
Type:
Article
ISSN:
0021-9606; 1089-7690
Sponsors:
This project was supported by the National Natural Science Foundation of China (Grant No. 61321001) and the MOST of China (Grant Nos. 2011CB933001 and 2013CB933404). S. S. thanks additional funding support from the European Research Council (QUEST project), by KAUST (FIC/2010/08), and by AMBER.
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Publications Acknowledging KAUST Support

Full metadata record

DC FieldValue Language
dc.contributor.authorWu, Kunlinen
dc.contributor.authorBai, Meilinen
dc.contributor.authorSanvito, Stefanoen
dc.contributor.authorHou, Shiminen
dc.date.accessioned2016-02-28T06:35:22Zen
dc.date.available2016-02-28T06:35:22Zen
dc.date.issued2014-07-07en
dc.identifier.citationWu K, Bai M, Sanvito S, Hou S (2014) Transition voltages of vacuum-spaced and molecular junctions with Ag and Pt electrodes. J Chem Phys 141: 014707. Available: http://dx.doi.org/10.1063/1.4886378.en
dc.identifier.issn0021-9606en
dc.identifier.issn1089-7690en
dc.identifier.pmid25005303en
dc.identifier.doi10.1063/1.4886378en
dc.identifier.urihttp://hdl.handle.net/10754/600066en
dc.description.abstractThe transition voltage of vacuum-spaced and molecular junctions constructed with Ag and Pt electrodes is investigated by non-equilibrium Green's function formalism combined with density functional theory. Our calculations show that, similarly to the case of Au-vacuum-Au previously studied, the transition voltages of Ag and Pt metal-vacuum-metal junctions with atomic protrusions on the electrode surface are determined by the local density of states of the p-type atomic orbitals of the protrusion. Since the energy position of the Pt 6p atomic orbitals is higher than that of the 5p/6p of Ag and Au, the transition voltage of Pt-vacuum-Pt junctions is larger than that of both Ag-vacuum-Ag and Au-vacuum-Au junctions. When one moves to analyzing asymmetric molecular junctions constructed with biphenyl thiol as central molecule, then the transition voltage is found to depend on the specific bonding site for the sulfur atom in the thiol group. In particular agreement with experiments, where the largest transition voltage is found for Ag and the smallest for Pt, is obtained when one assumes S binding at the hollow-bridge site on the Ag/Au(111) surface and at the adatom site on the Pt(111) one. This demonstrates the critical role played by the linker-electrode binding geometry in determining the transition voltage of devices made of conjugated thiol molecules. © 2014 AIP Publishing LLC.en
dc.description.sponsorshipThis project was supported by the National Natural Science Foundation of China (Grant No. 61321001) and the MOST of China (Grant Nos. 2011CB933001 and 2013CB933404). S. S. thanks additional funding support from the European Research Council (QUEST project), by KAUST (FIC/2010/08), and by AMBER.en
dc.publisherAIP Publishingen
dc.titleTransition voltages of vacuum-spaced and molecular junctions with Ag and Pt electrodesen
dc.typeArticleen
dc.identifier.journalThe Journal of Chemical Physicsen
dc.contributor.institutionKey Laboratory for the Physics and Chemistry of Nanodevices, Department of Electronics, Peking University, Beijing 100871, Chinaen
dc.contributor.institutionSchool of Physics, AMBER and CRANN Institute, Trinity College, Dublin 2, Irelanden
kaust.grant.numberFIC/2010/08en

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