Current-Induced Embrittlement of Atomic Wires

Abstract

Recent experiments suggest that gold single-atom contacts and atomic chains break at applied voltages of 1 to 2 V. In order to understand why current flow affects these defect-free conductors, we have calculated the current-induced forces on atoms in a Au chain between two Au electrodes. These forces are not by themselves sufficient to rupture the chain. However, the current reduces the work to break the chain, which results in a dramatic increase in the probability of thermally activated spontaneous fracture of the chain. This current-induced embrittlement poses a fundamental limit to the current-carrying capacity of atomic wires.

Coupled electron and phonon transport in one-dimensional atomic junctions

“…If the electron-phonon interaction is weak, the energy dissipated into the phonon system is only a small fraction of the electron energy current. But this small fraction still influences the transport properties of the atomic junction and even leads to junction breakup 32,33 , especially when the thermal conductance is low. Different models have been used to study the local heating effect.…”

“…Some simply assume that the phonons are in their thermal equilibrium states 31 . Some take into account the phonon transport by using the rate equations 30 or other semi-classical models 26,27,32 . Few of them take into account the quantum effect in heat transport 18,34 .…”

Nonconservative dynamics in long atomic wires

“…Constructive work leads to the possibility of nanoscale engines, while destructive work can act as an activation mechanism for electromigration and device failure [17]. Nonconservative forces may be a prime candidate for explaining apparent heating in atomic wires [18,19] far above that expected from Joule heating alone [20,21].…”

Theoretical study of linear monoatomic nanowires, dimer and bulk of Cu, Ag, Au, Ni, Pd and Pt

“…Metal nanowires have recently attracted a great deal of attention due to their unusual properties and relative simplicity of fabrication. Most studied systems both experimentally [1][2][3][4][5][6][7] and theoretically [8][9][10][11][12][13][14][15][16] are free standing gold nanowires, which exhibit a quantized conductance at stretching and have peculiar structural properties. Unsupported and supported wires of Cu, Pd, Pt, Ag and Au have also been studied theoretically by means of ab initio and molecular dynamics methods [14], [17][18][19][20][21][22].…”