Current-induced atomic dynamics, instabilities, and Raman signals: Quasi-classical Langevin equation approach

Abstract

We derive and employ a semi-classical Langevin equation obtained from path-integrals to describe the ionic dynamics of a molecular junction in the presence of electrical current. The electronic environment serves as an effective non-equilibrium bath. The bath results in random forces describing Joule heating,current-induced forces including the non-conservative wind force,dissipative frictional forces, and an effective Lorentz-like force due to the Berry phase of the non-equilibrium electrons. Using a generic two-level molecular model, we highlight the importance of both current-induced forces and Joule heating for the stability of the system. We compare the impact of the different forces, and the wide-band approximation for the electronic structure on our result. We examine the current-induced instabilities (excitation of runaway "waterwheel" modes) and investigate the signature of these in the Raman signals.

PRB accepted version

References in corpus (22)

• Molecular Transport Junctions: Vibrational Effects
• Quantum thermal transport in nanostructures
• Inelastic transport theory from first-principles: methodology and applications for nanoscale devices
• Nonequilibrium Green's Function Approach to Phonon Transport in Defective Carbon Nanotubes
• Electromigrated nanoscale gaps for surface-enhanced Raman spectroscopy
• Vibrational sidebands and dissipative tunneling in molecular transistors
• Vibrational and electronic heating in nanoscale junctions
• Nonequilibrium Green's function approach to mesoscopic thermal transport
• Inelastic scattering and local heating in atomic gold wires
• Modeling inelastic phonon scattering in atomic- and molecular-wire junctions
• Unified description of inelastic propensity rules for electron transport through nanoscale junctions
• Heat transport in harmonic lattices
• Resonant electron heating and molecular phonon cooling in single C${}_{60}$ junctions
• Scattering theory of current-induced forces in mesoscopic systems
• Quantum thermal transport from classical molecular dynamics
• Coupled electron and phonon transport in one-dimensional atomic junctions
• The transfer of energy between electrons and ions in solids
• An off-board quantum point contact as a sensitive detector of cantilever motion
• Laser-like vibrational instability in rectifying molecular conductors
• Semi-classical dynamics of nano-electromechanical systems
• Inelastic quantum transport: the self-consistent Born approximation and correlated electron-ion dynamics
• Scattering approach to backaction in coherent nanoelectromechanical systems

Cited by in corpus (10)

• Classical nuclear motion coupled to electronic non-adiabatic transitions
• Scattering theory of adiabatic reaction forces due to out-of-equilibrium quantum environments
• Current-induced forces: a simple derivation
• Current-induced forces and hot-spots in biased nano-junctions
• Out-of-equilibrium catalysis of chemical reactions by electronic tunnel currents
• Effects of electron-phonon interaction on thermal and electrical transport through molecular nano-conductors
• Phonon dynamics in correlated quantum systems driven away from equilibrium
• Electron-vibration effects on the thermoelectric efficiency of molecular junctions
• Nonconservative dynamics in long atomic wires
• An ignition key for atomic-scale engines