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

Article

关键词: ELECTRON-TUNNELING SPECTROSCOPY;    MOLECULAR-TRANSPORT JUNCTIONS;    CURRENT-INDUCED FORCES;    GOLD ATOMS;    CONDUCTANCE;    CONTACTS;    MICROSCOPY;    SCATTERING;    ENERGY;    MOTION;   

DOI  :  10.1103/PhysRevB.85.245444

来源: SCIE

【 摘 要 】

We derive and employ a semiclassical 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 nonequilibrium bath. The bath results in random forces describing Joule heating, current-induced forces including the nonconservative wind force, dissipative frictional forces, and an effective Lorentz-type force due to the Berry phase of the nonequilibrium 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.

【 授权许可】

Free