Simulating STM transport in alkanes from first principles

Toher, Cormac; Rungger, Ivan; Sanvito, Stefano

doi:10.1103/physrevb.79.205427

Cited by 26 publications

(32 citation statements)

References 35 publications

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“…In transport one wants ⑀ HOMO of the molecule of interest to correspond to the actual negative of its IP. 24,25 Although this should be the case for exact DFT, it happens only rather rarely in practice for the standard local approximations of the exchange and correlation functional. 26 In the case of liquid H 2 O the experimental value of the IP ranges between 9.3 ͑Ref.…”

Section: Au Capacitor In Watermentioning

confidence: 99%

Finite-bias electronic transport of molecules in a water solution

et al. 2010

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The effects of water wetting conditions on the transport properties of molecular nanojunctions are investigated theoretically by using a combination of empirical-potential molecular-dynamics and first-principles electronic-transport calculations. These are at the level of the nonequilibrium Green's-function method implemented for self-interaction corrected density-functional theory. We find that water effectively produces electrostatic gating to the molecular junction with a gating potential determined by the time-averaged water dipole field. Such a field is large for the polar benzene-dithiol molecule, resulting in a transmission spectrum shifted by about 0.6 eV with respect to that of the dry junction. The situation is drastically different for carbon nanotubes ͑CNTs͒. In fact, because of their hydrophobic nature the gating is almost negligible so that the average transmission spectrum of wet Au/CNT/Au junctions is essentially the same as that in dry conditions. This suggests that CNTs can be used as molecular interconnects also in water-wet situations, for instance, as tips for scanning tunnel microscopy in solution or in biological sensors.

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Section: Au Capacitor In Watermentioning

confidence: 99%

Finite-bias electronic transport of molecules in a water solution

et al. 2010

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“…If the molecular LUMO states have negative electron affinity, then the vacuum states will be lower in energy. Inclusion of such delocalized vacuum states within localized orbital basis sets calculations can be achieved by adding additional basis orbitals in the vacuum region [48]. However, vacuum states are neglected in the present study, which only concerns with molecular states.…”

Section: Methodsmentioning

confidence: 99%

Fundamental gap of molecular crystals via constrained density functional theory

et al. 2016

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The energy gap of a molecular crystal is one of the most important properties since it determines the crystal charge transport when the material is utilized in electronic devices. This is, however, a quantity difficult to calculate and standard theoretical approaches based on density functional theory (DFT) have proven unable to provide accurate estimates. In fact, besides the well-known band-gap problem, DFT completely fails in capturing the fundamental gap reduction occurring when molecules are packed in a crystal structures. The failure has to be associated with the inability of describing the electronic polarization and the real space localization of the charged states. Here we describe a scheme based on constrained DFT, which can improve upon the shortcomings of standard DFT. The method is applied to the benzene crystal, where we show that accurate results can be achieved for both the band gap and also the energy level alignment.

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“…Since first proposed by Aviram and Ratner, 1 molecular rectifier has gained considerable attention in both experimental designs [2][3][4][5] and theoretical simulations. 6,7 One of the most promising candidates stems from a molecular heterojunction which describes a molecular junction with asymmetric conformation. The asymmetric conformation of a molecular junction was believed to lead to asymmetric electronic behavior such as asymmetric I-V characteristics, a marked feature for future applications as a molecular diode.…”

Section: Introductionmentioning

confidence: 99%

Measurement and understanding of single-molecule break junction rectification caused by asymmetric contacts

Wang

Zhou

Hamill

et al. 2014

The Journal of Chemical Physics

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The contact effects of single-molecule break junctions on rectification behaviors were experimentally explored by a systematic control of anchoring groups of 1,4-disubstituted benzene molecular junctions. Single-molecule conductance and I-V characteristic measurements reveal a strong correlation between rectifying effects and the asymmetry in contacts. Analysis using energy band models and I-V calculations suggested that the rectification behavior is mainly caused by asymmetric coupling strengths at the two contact interfaces. Fitting of the rectification ratio by a modified Simmons model we developed suggests asymmetry in potential drop across the asymmetric anchoring groups as the mechanism of rectifying I-V behavior. This study provides direct experimental evidence and sheds light on the mechanisms of rectification behavior induced simply by contact asymmetry, which serves as an aid to interpret future single-molecule electronic behavior involved with asymmetric contact conformation.

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Simulating STM transport in alkanes from first principles

Cited by 26 publications

References 35 publications

Finite-bias electronic transport of molecules in a water solution

Finite-bias electronic transport of molecules in a water solution

Fundamental gap of molecular crystals via constrained density functional theory

Measurement and understanding of single-molecule break junction rectification caused by asymmetric contacts

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