Jumps in electronic conductance due to mechanical instabilities

Todorov, Tchavdar N.; Sutton, A. P.

doi:10.1103/physrevlett.70.2138

Cited by 214 publications

(185 citation statements)

References 23 publications

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“…Such models are of course inadequate to describe electrical conduction, so to explain the observed correlations in the conductance and force of metallic nanowires, a quantum-mechanical model whose geometry is fit to the results of the classical simulation is constructed. [21][22][23] The cost of working in a localized basis is thus the necessity of using different physical laws to describe conductance and cohesion.…”

Section: Discussionmentioning

confidence: 99%

“…A final word should be added by way of addressing the central controversy of this field, which can be stated as follows: Is it the atomic structure (i.e., the bonds) which determines the conductance, [21][22][23]39 or should the conductance channels themselves be thought of as mesoscopic bonds which provide the cohesion, and thus determine the structure?…”

Section: Discussionmentioning

confidence: 99%

“…Thus molecular dynamics simulations [21][22][23] typically neglect any quantum coherence between different bonds, and amount to a computational version of the classical ball-and-stick model of atomic structure, where bonds are described by a shortranged empirical inter-atomic potential. This is an uncontrolled approximation, which should be adequate to describe covalent bonds in an insulator, but its applicability for monovalent metals with nearly spherical Fermi surfaces like Au and Na is questionable.…”

Section: Discussionmentioning

confidence: 99%

“…15 in terms of a simple physical picture, which was essentially the converse of the conventional interpretation. The conventional interpretation [21][22][23] of the experiments of Refs. 4,5 is that the jumps in the conductance are due to abrupt changes of the structure of the nanowire at the atomic level, e.g., through the breaking of bonds, and that these structural rearrangements manifested themselves as abrupt changes in the cohesive force.…”

Section: E Local Density Of Statesmentioning

confidence: 99%

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Force, charge, and conductance of an ideal metallic nanowire

1999

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The conducting and mechanical properties of a metallic nanowire formed at the junction between two macroscopic metallic electrodes are investigated. Both two-and three-dimensional wires with a W(ide)-N(arrow)-W(ide) geometry are modelled in the free-electron approximation with hard-wall boundary conditions. Tunneling and quantum-size effects are treated exactly using the scattering matrix formalism. Oscillations of order EF /λF in the tensile force are found when the wire is stretched to the breaking point, which are synchronized with quantized jumps in the conductance. The force and conductance are shown to be essentially independent of the width of the wide sections (electrodes). The exact results are compared with an adiabatic approximation; the later is found to overestimate the effects of tunneling, but still gives qualitatively reasonable results for nanowires of length L ≫ λF , even for this abrupt geometry. In addition to the force and conductance, the net charge of the nanowire is calculated and the effects of screening are included within linear response theory. Mesoscopic charge fluctuations of order e are predicted which are strongly correlated with the mesoscopic force fluctuations. The local density of states at the Fermi energy exhibits nontrivial behavior which is correlated with fine structure in the force and conductance, showing the importance of treating the whole wire as a mesoscopic system rather than treating only the narrow part.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: E Local Density Of Statesmentioning

confidence: 99%

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Force, charge, and conductance of an ideal metallic nanowire

1999

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“…The conductance of Au ASWs is related to a unit of G 0 , although the conductance deviates owing to irregularities in the wire shape, the convergent angle of electrodes, and the expansion of the interatomic distance. 19,[26][27][28] The geometry and roughness of the contact surfaces including electrodes also contribute to the conductance. 15 In conductance histograms of Pt and Ir NCs, peaks are not observed at quantized values, and the peaks are wider than those of Au NCs.…”

Section: Introductionmentioning

confidence: 99%

Atomic configuration, conductance, and tensile force of platinum wires of single-atom width

Kizuka

Monna

2009

Phys. Rev. B

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Platinum ͑Pt͒ wires of single-atom width were produced by the retraction of a Pt nanotip from contact with a Pt plate at room temperature inside a transmission electron microscope. The distance between the nanotip and the plate was controlled using a conductance feedback system, as a result of which wires showing certain conductance values were observed continuously by in situ lattice imaging. Simultaneously, the force acting on the wires was measured using a function of atomic force microscopy. The tip-plate distance was also increased with a constant speed, and the atomic configuration, force, and conductance were similarly investigated. The single-atom-width Pt wires were found to exhibit straight shapes with an interatomic distance of 0.28Ϯ 0.03 nm. The wires were stable at a tensile force of approximately 1 nN; the observed interatomic distance resulted from elastic expansion. The present study demonstrated experimental evidence for the relationship between wire length and conductance; the wires extend from a three-atom length to a five-atom length as the selected feedback conductance decreases from 2.0 to 0.5G 0 ͑where G 0 =2e 2 / h, e being the charge of an electron and h Planck's constant͒. Contacts exhibiting a conductance of 3.0G 0 were two-atom-width contacts. In a conductance histogram constructed from the simple retraction, only one peak was observed at 1.3G 0 . Thus, it was found that the conductance of single-atom-width Pt wires is less than 3.0G 0 , with 1.3G 0 being that of the most-stable state.

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Atomic Arrangement and Conductance of Metal Nanowires

Ugarte

2002

phys. stat. sol. (b)

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We have used high resolution transmission electron microscopy and mechanically controllable break junction technique to study metal NW structure and electrical transport properties. In the last stages just before rupture, gold and platinum nanowires are crystalline and defect-free. In particular, gold NWs assume merely three kinds of atomic arrangements, which were correlated to observed conductance behaviors.Introduction The interest in nanometric systems has grown because they show intriguing new effects, which can be used to study quantum phenomena and to generate novel electronic devices. One of these systems is the metal nanowire (NW), which has attracted great attention due to its quantized conductance. NWs can be obtained in a simple way by putting in contact two clean metal surfaces and subsequently separating them; NWs are generated during the contact breaking. Just before rupture, conductance measurements display flat plateaus connected by abrupt jumps whose value is approximately a conductance quantum G 0 ¼ 2e 2 =h (where e is the electron charge and h is Planck's constant) [1]. In this kind of experiment, each new measurement corresponds to a different metal NW and conductance curves show dissimilar profiles [2], raising the question about the role of structural and electronic effects on the conductance changes.In this work, we have analyzed gold and platinum NWs generated by mechanical elongation, using a high resolution transmission electron microscope. We have observed that, just before rupture, metal NWs are crystalline and defect-free. Also, for gold, we reduced the number of possible NW atomic configuration to only three cases. Using a simple geometrical model we have estimated the conductance behavior for each NW type and its occurrence probabilities, that showed a remarkable agreement with experimental data measured with a mechanically controllable break junction.

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Jumps in electronic conductance due to mechanical instabilities

Cited by 214 publications

References 23 publications

Force, charge, and conductance of an ideal metallic nanowire

Force, charge, and conductance of an ideal metallic nanowire

Atomic configuration, conductance, and tensile force of platinum wires of single-atom width

Atomic Arrangement and Conductance of Metal Nanowires

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