Cooling molecular electronic junctions by AC current

Abstract

Electronic current flowing in a molecular electronic junction dissipates significant amounts of energy to vibrational degrees of freedom, straining and rupturing chemical bonds and often quickly destroying the integrity of the molecular device. The infamous mechanical instability of molecular electronic junctions critically limits performance, lifespan, and raises questions as to the technological viability of single-molecule electronics. Here we propose a practical scheme for cooling the molecular vibrational temperature via application of an AC voltage over a large, static operational DC voltage bias. Using nonequilibrium Green's functions, we computed the viscosity and diffusion coefficient experienced by nuclei surrounded by a nonequilibrium "sea" of periodically driven, current-carrying electrons. The effective molecular junction temperature is deduced by balancing the viscosity and diffusion coefficients. Our calculations show the opportunity of achieving in excess of 40\% cooling of the molecular junction temperature while maintaining the same average current.

References in corpus (4)

• Current-induced atomic dynamics, instabilities, and Raman signals: Quasi-classical Langevin equation approach
• Ground-state cooling of a carbon nanomechanical resonator by spin-polarized current
• Out-of-equilibrium catalysis of chemical reactions by electronic tunnel currents
• Timescale separation solution of Kadanoff-Baym equations for quantum transport in time-dependent fields