Nonconservative current-driven dynamics: beyond the nanoscale

Brian Cunningham*, Tchavdar N. Todorov, Daniel Dundas

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

Long metallic nanowires combine crucial factors for nonconservative current-driven atomic motion. These systems have degenerate vibrational frequencies, clustered about a Kohn anomaly in the dispersion relation, that can couple under current to form nonequilibrium modes of motion growing exponentially in time. Such motion is made possible by nonconservative current-induced forces on atoms, and we refer to it generically as the waterwheel effect. Here the connection between the waterwheel effect and the stimulated directional emission of phonons propagating along the electron flow is discussed in an intuitive manner. Nonadiabatic molecular dynamics show that waterwheel modes self-regulate by reducing the current and by populating modes in nearby frequency, leading to a dynamical steady state in which nonconservative forces are counter-balanced by the electronic friction. The waterwheel effect can be described by an appropriate effective nonequilibrium dynamical response matrix. We show that the current-induced parts of this matrix in metallic systems are long-ranged, especially at low bias. This nonlocality is essential for the characterisation of nonconservative atomic dynamics under current beyond the nanoscale.

Original languageEnglish
Pages (from-to)2140-2147
Number of pages8
JournalBeilstein Journal of Nanotechnology
Volume6
Issue number1
DOIs
Publication statusPublished - 13 Nov 2015

Keywords

  • Atomic-scale conductors
  • Current-induced forces
  • Electronic transport
  • Failure mechanisms
  • Nanoelectronic devices
  • Nanomotors

ASJC Scopus subject areas

  • Materials Science(all)
  • Electrical and Electronic Engineering
  • Physics and Astronomy(all)

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