Single-molecule device prototypes for protein-based nanoelectronics: Negative differential resistance and current rectification in oligopeptides

Cardamone, David; Kirczenow, George

doi:10.1103/physrevb.77.165403

Cited by 40 publications

(50 citation statements)

References 35 publications

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“…To couple the extended molecule to the electron reservoirs, as in previous work [14][15][16][19][20][21][22][23][24][25], we attach a large number of semi-infinite quasi-one-dimensional ideal leads to the valence orbitals of the outer gold atoms of the extended molecule. We find the transmission amplitudes t ji by solving the Lippmann-Schwinger equation…”

Section: Conductance Calculationsmentioning

confidence: 99%

Mechanism of the enhanced conductance of a molecular junction under tensile stress

2014

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Despite its fundamental importance for nano physics and chemistry and potential device applications, the relationship between atomic structure and electronic transport in molecular nanostructures is not well understood. Thus the experimentally observed increase of the conductance of some molecular nano junctions when they are stretched continues to be counterintuitive and controversial. Here we explore this phenomenon in propanedithiolate molecules bridging gold electrodes by means of ab initio computations and semi-empirical modeling. We show that in this system it is due to changes in Au-S-C bond angles and strains in the gold electrodes, rather than to the previously proposed mechanisms of Au-S bond stretching and an associated energy shift of the highest occupied molecular orbital and/or Au atomic chain formation. Our findings indicate that conductance enhancement in response to the application of tensile stress should be a generic property of molecular junctions in which the molecule is thiol-bonded in a similar way to gold electrodes.

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Section: Conductance Calculationsmentioning

confidence: 99%

Mechanism of the enhanced conductance of a molecular junction under tensile stress

2014

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“…72 The extended Hückel model 50 is a semiempirical tight-binding scheme that provides a simple but reasonably realistic description of the electronic structures of many molecules. It has been used successfully in explaining and predicting experimental transport properties of a variety of molecular systems, 50 including conduction in molecular wires bridging metal contacts [73][74][75][76][77][78][79] and molecular arrays on silicon [80][81][82] and the electroluminescence, 83 current-voltage characteristics, 83 and STM images 84 of molecules on complex substrates. Thus it offers a natural way to extend the standard tight-binding model of pristine graphene 59 to the case of graphene with adsorbates.…”

Section: Introductionmentioning

confidence: 99%

Dirac point resonances due to atoms and molecules adsorbed on graphene and transport gaps and conductance quantization in graphene nanoribbons with covalently bonded adsorbates

Ihnatsenka

Kirczenow

2011

Phys. Rev. B

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We present a tight-binding theory of the Dirac point resonances due to adsorbed atoms and molecules on an infinite two-dimensional graphene sheet based on the standard tight-binding model of the graphene π -band electronic structure and the extended Hückel model of the adsorbate and nearby graphene carbon atoms. The relaxed atomic geometries of the adsorbates and graphene are calculated using density functional theory. Our model includes the effects of local rehybridization of the graphene from the sp 2 to sp 3 electronic structures that occurs when adsorbed atoms or molecules bond covalently to the graphene. Unlike in previous tight-binding models of Dirac point resonances, adsorbed species with multiple extended molecular orbitals and bonding to more than one graphene carbon atom are treated. More accurate and more general analytic expressions for the Green's function matrix elements that enter the T -matrix theory of Dirac point resonances than have been available previously are obtained. We study H, F, OH, and O adsorbates on graphene and for each we find a strong scattering resonance (two resonances for O) near the Dirac point of graphene, by far the strongest and closest to the Dirac point being the resonance for H. We extract a minimal set of tight-binding parameters that can be used to model resonant electron scattering and electron transport in graphene and graphene nanostructures with adsorbed H, F, OH, and O accurately and efficiently. We also compare our results for the properties of Dirac point resonances due to adsorbates on graphene with those obtained by others using density-functional-theory-based electronic structure calculations and discuss their relative merits. We then present calculations of electronic quantum transport in graphene nanoribbons with these adsorbed species. Our transport calculations capture the physics of the scattering resonances that are induced in the graphene ribbons near the Dirac point by the presence of the adsorbates. We find that the Dirac point resonances play a dominant role in quantum transport in ribbons with adsorbates: Even at low adsorbate concentrations the conductance of the ribbon is strongly suppressed and a transport gap develops for electron Fermi energies near the resonance. The transport gap is centered very near the Dirac point energy for H, below it for F and OH, and above it for O. We find conduction in ribbons with adsorbed H atoms to be very similar to that in ribbons with equal concentrations of carbon atom vacancies. We predict ribbons with adsorbed H, F, OH, and O, under appropriate conditions, to exhibit quantized conductance steps of equal height, similar to those that have been observed by Lin et al. [Phys. Rev. B 78, 161409(R) (2008)] at moderately low temperatures, even for ribbons with conductances a few orders of magnitude smaller than 2e 2 /h.

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“…v j and v i are the corresponding electron velocities. The coupling of the extended molecule to the electron reservoirs was treated as in previous work [75,78,[85][86][87][88][89][90][91][92][93][94] by attaching a large number of semi-infinite quasi-one-dimensional ideal leads to the valence orbitals of the outer gold atoms of the extended molecule.…”

Section: Theorymentioning

confidence: 99%

Inelastic tunneling spectroscopy of gold-thiol and gold-thiolate interfaces in molecular junctions: The role of hydrogen

Demir

Kirczenow

2012

The Journal of Chemical Physics

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It is widely believed that when a molecule with thiol (S-H) end groups bridges a pair of gold electrodes, the S atoms bond to the gold and the thiol H atoms detach from the molecule. However, little is known regarding the details of this process, its time scale, and whether molecules with and without thiol hydrogen atoms can coexist in molecular junctions. Here we explore theoretically how inelastic tunneling spectroscopy (IETS) can shed light on these issues. We present calculations of the geometries, low bias conductances and IETS of propanedithiol and propanedithiolate molecular junctions with gold electrodes. We show that IETS can distinguish between junctions with molecules having no, one or two thiol hydrogen atoms. We find that in most cases the single-molecule junctions in the IETS experiment of Hihath et al. [Nano Lett. 8, 1673(2008] had no thiol H atoms, but that a molecule with a single thiol H atom may have bridged their junction occasionally. We also consider the evolution of the IETS spectrum as a gold STM tip approaches the intact S-H group at the end of a molecule bound at its other end to a second electrode. We predict the frequency of a vibrational mode of the thiol H atom to increase by a factor ∼ 2 as the gap between the tip and molecule narrows. Therefore, IETS should be able to track the approach of the tip towards the thiol group of the molecule and detect the detachment of the thiol H atom from the molecule when it occurs.

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Single-molecule device prototypes for protein-based nanoelectronics: Negative differential resistance and current rectification in oligopeptides

Cited by 40 publications

References 35 publications

Mechanism of the enhanced conductance of a molecular junction under tensile stress

Mechanism of the enhanced conductance of a molecular junction under tensile stress

Dirac point resonances due to atoms and molecules adsorbed on graphene and transport gaps and conductance quantization in graphene nanoribbons with covalently bonded adsorbates

Inelastic tunneling spectroscopy of gold-thiol and gold-thiolate interfaces in molecular junctions: The role of hydrogen

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