Directed current in the Holstein system

TL;DR

This paper introduces a mechanism for rectifying charge transport in the Holstein model by combining localized initial conditions with asymmetric on-site potentials, leading to directed current and long-range charge transport.

Contribution

It demonstrates that localised initial conditions and asymmetric potentials can induce directed current in a symmetric, time-reversible Holstein system, a novel insight into charge transport mechanisms.

Findings

Directed current arises from localized initial conditions and asymmetric potentials.

Violation of parity prevents counter-propagating trajectories, enabling directed transport.

Long-range coherent charge transport is observed.

Abstract

We propose a mechanism to rectify charge transport in the semiclassical Holstein model. It is shown that localised initial conditions, associated with a polaron solution, in conjunction with a nonreversion symmetric static electron on-site potential constitute minimal prerequisites for the emergence of a directed current in the underlying periodic lattice system. In particular, we demonstrate that for unbiased spatially localised initial conditions, violation of parity prevents the existence of pairs of counter-propagating trajectories, thus allowing for a directed current despite the time-reversibility of the equations of motion. Occurrence of long-range coherent charge transport is demonstrated.