Benzenedithiol: A Broad-Range Single-Channel Molecular Conductor

Kim, Young-Sang; Pietsch, Torsten; Erbe, Artur; Belzig, Wolfgang; Scheer, Elke

doi:10.1021/nl201777m

Cited by 195 publications

(285 citation statements)

References 35 publications

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“…In fact, in a single experiment, a broad range of values of conductance, G, is observed, and possibly even very different average G values between experiments. 2,9,12 Yet, recent independent measurements 5,19,22,24 are in agreement on an average value of G of about 0.01G 0 , where G 0 = 2e 2 /h is the quantum conductance (e is the electron charge and h is the Planck's constant).…”

Section: Introductionmentioning

confidence: 54%

Stretching of BDT-gold molecular junctions: thiol or thiolate termination?

et al. 2014

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It is often assumed that the hydrogen atoms in the thiol groups of a benzene-1,4-dithiol dissociate when Au-benzene-1,4-dithiol-Au junctions are formed. We demonstrate, by stability and transport property calculations, that this assumption cannot be made. We show that the dissociative adsorption of methanethiol and benzene-1,4-dithiol molecules on a flat Au(111) surface is energetically unfavorable and that the activation barrier for this reaction is as high as 1 eV. For the molecule in the junction, our results show, for all electrode geometries studied, that the thiol junctions are energetically more stable than their thiolate counterparts. Due to the fact that density functional theory (DFT) within the local density approximation (LDA) underestimates the energy difference between the lowest unoccupied molecular orbital and the highest occupied molecular orbital by several electron-volts, and that it does not capture the renormalization of the energy levels due to the image charge effect, the conductance of the Au-benzene-1,4-dithiol-Au junctions is overestimated. After taking into account corrections due to image charge effects by means of constrained-DFT calculations and electrostatic classical models, we apply a scissor operator to correct the DFT energy level positions, and calculate the transport properties of the thiol and thiolate molecular junctions as a function of the electrode separation. For the thiol junctions, we show that the conductance decreases as the electrode separation increases, whereas the opposite trend is found for the thiolate junctions. Both behaviors have been observed in experiments, therefore pointing to the possible coexistence of both thiol and thiolate junctions. Moreover, the corrected conductance values, for both thiol and thiolate, are up to two orders of magnitude smaller than those calculated with DFT-LDA.This brings the theoretical results in quantitatively good agreement with experimental data.

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Section: Introductionmentioning

confidence: 54%

Stretching of BDT-gold molecular junctions: thiol or thiolate termination?

et al. 2014

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“…Currently, IV curve measurements are used as the standard technique to study the electronic structure of the single-molecule junctions. 41,65,66 Through the development of these spectroscopic techniques, we have revealed the atomic and electronic structures of singlemolecule junctions, and we now can observe single-molecule junctions. Furthermore, these studies have changed the type and direction of research into single-molecule junctions, where once only conductance was discussed.…”

Section: ¹1mentioning

confidence: 99%

“…Since then, IETS have been applied to various single-molecule junctions, including alkanedithiol, ethylene, and acetylene. 9,41,42,47 IETS is based on electronic current modulation due to the interaction between the conduction electrons and vibrations of the single-molecule junction. In addition, point contact spectroscopy (PCS) and action spectroscopy can detect the vibrational modes of the single-molecule junction based on these interactions.…”

mentioning

confidence: 99%

Governing the Metal–Molecule Interface: Towards New Functionality in Single-Molecule Junctions

Kiguchi¹,

Fujii²

2016

Bulletin of the Chemical Society of Japan

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Single-molecule junctions, in which a single molecule bridges a gap between metal electrodes, have attracted significant attention due to their potential applications in ultrasmall electronic devices and their unique structure. Singlemolecule junctions are one-dimensional nanomaterials having two metalmolecule interfaces. Thus, unconventional properties and functionalities that would not be observed in other phases (e.g., isolated molecules and bulk crystals) are expected to appear in these nanomaterials. Despite interest in these expected unconventional properties, several issues have been noted with the investigation and practical application of the unique properties of single-molecule junctions.To explore new functionality, we have investigated singlemolecule junctions using a combined approach comprising fabrication, characterization, and measurement. First, we have explored a new generation of the metalmolecule interfaces formed by direct π-bonding. The interfaces made by the direct π-bonding have increased electronic conductance at the singlemolecule junction, reaching the theoretical limit, 1 G 0 (2e 2 /h), which is the conductance of typical metal monoatomic contacts. Secondly, we have developed new characterization techniques combined with a variety of spectroscopic methods to observe a single molecule confined between metal electrodes. This has allowed us to reveal structural and electronic details of single-molecule junctions, such as the number of molecules, molecular species, interface-structure, electronic structure, and dynamics. Based on the development of the metalmolecule interface structures and the combined spectroscopic characterization techniques, we have searched for new single-molecule junction functionality. By controlling the metalmolecule interface structures, single molecular switching functionality with multiple conductance states and a programmable singlemolecule junction with various electronic functionalities have been realized. Our newly developed interface structure, characterization technique, and the functionality of the singlemolecule junction opens the door for future research in the field of single-molecule junctions.

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“…Hence, there will be no current flowing between the leads. Placing an active element like a molecule between these leads will thus induce a transport path and, when voltage or temperature differences between the leads are imposed, thermoelectric phenomena [5][6][7][8][9][10]. The coupling of the molecule and the leads will be quantum mechanical, i.e., one can usually assume that the coupling that gives rise to a transfer of mobile electrons from the leads onto the molecule is governed by tunneling processes.…”

Section: Introductionmentioning

confidence: 99%

Thermoelectricity in tunneling nanostructures

et al. 2015

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We employ a simple analyic model to calculate the thermopower of low transparency molecular nanosystems. It turns out that the sign of the thermovoltage for this model depends sensitively on the participating molecular orbital, and one finds a sign change when the transport channel switches from the highest occupied molecular orbital to the lowest unoccupied molecular orbital. Comparing our results to recent experimental data obtained for a BDT molecule contacted with an STM tip, we observe good agreement.

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Benzenedithiol: A Broad-Range Single-Channel Molecular Conductor

Cited by 195 publications

References 35 publications

Stretching of BDT-gold molecular junctions: thiol or thiolate termination?

Stretching of BDT-gold molecular junctions: thiol or thiolate termination?

Governing the Metal–Molecule Interface: Towards New Functionality in Single-Molecule Junctions

Thermoelectricity in tunneling nanostructures

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