Classical Heat Transport in Anharmonic Molecular Junctions: Exact Solutions

TL;DR

This paper provides exact analytical solutions for classical heat transport in anharmonic molecular junctions, revealing how anharmonicity influences heat flux and cumulants, with implications for nanoscale thermal management.

Contribution

It derives exact steady state heat flux and cumulants for anharmonic junctions, highlighting the role of anharmonicity and providing a general formula for heat statistics.

Findings

Thermal conductance depends on temperature via an effective force constant.

Cumulants of heat are independent of nonlinear potential in a bounded oscillator.

Exact solutions for all heat cumulants are obtained for a specific anharmonic model.

Abstract

We study full counting statistics for classical heat transport through anharmonic/nonlinear molecular junctions formed by interacting oscillators. Analytical result of the steady state heat flux for an overdamped anharmonic junction with arbitrary temperature bias is obtained. It is found that the thermal conductance can be expressed in terms of temperature dependent effective force constant. The role of anharmonicity is identified. We also give the general formula for the second cumulant of heat in steady state, as well as the average geometric heat flux when two temperatures are modulated adiabatically. We present an anharmonic example for which all cumulants for heat can be obtained exactly. For a bounded single oscillator model with mass we found that the cumulants are independent of the nonlinear potential.