Double negative differential thermal resistance induced by the nonlinear on-site potentials

TL;DR

This paper investigates how nonlinear on-site potentials in one-dimensional lattices induce double negative differential thermal resistance, revealing the roles of bounded and unbounded nonlinearities at different temperature regimes.

Contribution

It demonstrates that nonlinear on-site potentials are essential for NDTR in harmonic lattices and identifies the specific contributions of bounded and unbounded nonlinearities to NDTR.

Findings

NDTR occurs in specific temperature difference regions.

Bounded nonlinearity influences low-temperature NDTR.

Unbounded nonlinearity induces high-temperature NDTR.

Abstract

We study heat conduction through one-dimensional homogeneous lattices in the presence of the nonlinear on-site potentials containing the bounded and unbounded parts, and the harmonic interaction potential. We observe the occurrence of double negative differential thermal resistance (NDTR), namely, there exist two regions of temperature difference, where the heat flux decreases as the applied temperature difference increases. The nonlinearity of the bounded part contributes to NDTR at low temperatures and NDTR at high temperatures is induced by the nonlinearity of the unbounded part. The nonlinearity of the on-site potentials is necessary to obtain NDTR for the harmonic interaction homogeneous lattices. However, for the anharmonic homogeneous lattices, NDTR even occurs in the absence of the on-site potentials, for example the rotator model.