Key role of asymmetric interactions in low-dimensional heat transport

TL;DR

This study investigates how asymmetric interparticle interactions influence heat transport in one-dimensional lattices, revealing that asymmetry can lead to faster decay of heat current correlations and finite thermal conductivity.

Contribution

It demonstrates the correlation between interaction asymmetry and the decay rate of heat current autocorrelation functions in low-dimensional systems.

Findings

HCAF decays faster than power-law, sometimes exponentially.

Fast decay of HCAF implies finite heat conductivity.

Asymmetry degree influences the decay behavior of HCAF.

Abstract

We study the heat current autocorrelation function (HCAF) in one-dimensional, momentum-conserving lattices. In particular, we explore if there is any relation between the decaying characteristics of the HCAF and asymmetric interparticle interactions. The Lennard-Jones model is intensively investigated in view of its significance to applications. It is found that in wide ranges of parameters, the HCAF decays faster than power-law manners, and in some cases it decays even exponentially. Following the Green-Kubo formula, the fast decay of HCAF implies the convergence of heat conductivity, which is also corroborated by numerical simulations. In addition, with a comparison to the Fermi-Pasta-Ulam-$\beta$ model of symmetric interaction, the HCAF of the Fermi-Pasta-Ulam-$\alpha$-$\beta$ model of asymmetric interaction is also investigated. Our study suggests that, in certain ranges of parameters, the decaying behavior of the HCAF is correlated to the asymmetry degree of interaction.