Microscopic model of a phononic refrigerator

TL;DR

This paper presents a microscopic model of a nanomechanical system that demonstrates phononic refrigeration by modulating coupling to create a moving barrier, analyzed through numerical Green function methods.

Contribution

It introduces a simple microscopic model for phononic refrigeration using a time-dependent perturbation and numerical analysis, advancing understanding of nanoscale heat pumps.

Findings

The model achieves heat pumping from cold to hot reservoirs.

Low frequencies and sharp barriers are effective for refrigeration.

Numerical solutions confirm the feasibility of phonon refrigeration.

Abstract

We analyze a simple microscopic model to pump heat from a cold to a hot reservoir in a nanomechanical system. The model consists of a one-dimensional chain of masses and springs coupled to a back gate through which a time-dependent perturbation is applied. The action of the gate is to modulate the coupling of the masses to a substrate via additional springs that introduce a moving phononic barrier. We solve the problem numerically using non-equilibrium Green function techniques. For low driving frequencies and for sharp traveling barriers, we show that this microscopic model realizes a phonon refrigerator.