Quantized conductance in atom-sized wires between two metals

Mads Brandbyge, Jakob Schiøtz, Mads Reinholdt Sørensen, Per Stoltze, Karsten Wedel Jacobsen, Jens Kehlet Nørskov, Laurits Højgaard Olesen, E. Laegsgaard, I. Stensgaard, Flemming Besenbacher

Research output: Contribution to journalJournal articleResearchpeer-review

701 Downloads (Pure)

Abstract

We present experimental and theoretical results for the conductance and mechanical properties of atom-sized wires between two metals. The experimental part is based on measurements with a scanning tunneling microscope (STM) where a point contact is created by indenting the tip into a gold surface. When the tip is retracted, a 10-20 Angstrom long nanowire is formed. Our measurements of the conductance of nanowires show clear signs of a quantization in units of 2e(2)/h. The scatter around the integer values increases considerably with the number of quanta, and typically it is not possible to observe more than up to four quanta in these experiments. A detailed discussion is given of the statistical methods used in the analysis of the experimental data. The theoretical part of the paper addresses some questions posed by the experiment: Why can conductance quantization be observed, what is the origin of the scatter in the experimental data, and what is the origin of the scaling of the scattering with the number of conductance quanta? The theoretical discussion is based on a free-electron-like model where scattering from the boundary of the nanowire is included. The configurations of the nanowires are deduced from molecular dynamics simulations, which also give information about the mechanical properties of the system. We show that such a model can account semiquantitatively for several of the observed effects. One of the main conclusions of the theoretical analysis is that,; due to the plastic deformation of the nanowires formed by the STM, the typical length scale of the variations in the shape of the boundary is not an atomic radius but rather bye times that value. This is the reason why scattering is sufficiently small to make conductance quantization observable by STM.
Original languageEnglish
JournalPhysical Review B
Volume52
Issue number11
Pages (from-to)8499-8514
ISSN2469-9950
DOIs
Publication statusPublished - 1995

Bibliographical note

Copyright (1995) by the American Physical Society.

Keywords

  • ADHESION
  • TRANSPORT
  • SCALE
  • TRANSITION
  • POINT CONTACTS
  • SURFACES
  • BALLISTIC-RESISTANCE
  • SCANNING-TUNNELING-MICROSCOPY
  • STEPS
  • CONSTRICTIONS

Fingerprint

Dive into the research topics of 'Quantized conductance in atom-sized wires between two metals'. Together they form a unique fingerprint.

Cite this