Negative differential thermal resistance induced by ballistic transport

TL;DR

This paper investigates negative differential thermal resistance in two-segment Frenkel-Kontorova lattices using molecular dynamics and Landauer-based theory, revealing the transition from diffusive to ballistic transport and finite-size effects.

Contribution

It provides a theoretical and simulation-based analysis of the physical mechanisms behind negative differential thermal resistance in lattice systems.

Findings

Negative differential thermal resistance appears in the studied lattices.

The crossover from diffusive to ballistic transport is characterized.

Finite-size effects influence the thermal transport behavior.

Abstract

Using nonequilibrium molecular-dynamics simulations, we study the temperature dependence of the negative differential thermal resistance that appears in two-segment Frenkel-Kontorova lattices. We apply the theoretical method based on Landauer equation to obtain the relationship between the heat current and the temperature, which states a fundamental interpretation about the underlying physical mechanism of the negative differential thermal resistance. The temperature profiles and transport coefficients are demonstrated to explain the crossover from diffusive to ballistic transport. The finite-size effect is also discussed.