Nonequilibrium stationary states with ratchet effect

TL;DR

This paper investigates how an ensemble of particles in a thermal environment, modeled by Nosè-Hoover dynamics, can exhibit directed transport under a polarized microwave field, despite thermodynamic constraints, with applications to semiconductor superlattices.

Contribution

It provides a theoretical estimate of microwave-induced directed current in an antidot superlattice, highlighting the conditions for ratchet effects in nonequilibrium stationary states.

Findings

Directed transport emerges under polarized microwave fields.

Transport depends nontrivially on temperature and field parameters.

Theoretical estimates align with potential experimental setups.

Abstract

An ensemble of particles in thermal equilibrium at temperature $T$, modeled by Nos\`e-Hoover dynamics, moves on a triangular lattice of oriented semi-disk elastic scatterers. Despite the scatterer asymmetry a directed transport is clearly ruled out by the second law of thermodynamics. Introduction of a polarized zero mean monochromatic field creates a directed stationary flow with nontrivial dependence on temperature and field parameters. We give a theoretical estimate of directed current induced by a microwave field in an antidot superlattice in semiconductor heterostructures.