Hysteresis and effective reciprocity breaking due to current-induced forces

Abstract

Directed transport is a key concept for many ongoing applications including nanoscale heat management, current rectification, source protection, and energy harvesting. Within the context of quantum transport, we here explore the use of nonlinear effects introduced by current-induced forces (CIFs) as a practical way to effectively break charge and heat transport reciprocities. In particular, we consider a simple model consisting of a mobile quantum dot (QD) coupled to two leads, where the charge (or heat) current develops an asymmetric behavior under inversion of voltage (or temperature) bias, thereby turning the system into a quantum diode (or quantumthermal diode). Furthermore, we find multiple stable positions for the QD and we show how the extraction of useful work is possible by modulating the nonequilibrium sources along well-established hysteresis loops. Finally, we explore a particular case where the nonlinearity of the CIFs can be exploited to pump heat or charge, even for systems that preserve inversion symmetry. This counterintuitive result is attributed to a spontaneous breaking of the inversion symmetry due to the intrinsic system’s dynamics.