Thermal rectification in oscillator lattices with a ballistic spacer and next nearest-neighbor interactions

TL;DR

This study investigates how adding next-nearest-neighbor interactions in a mass-graded oscillator lattice enhances thermal rectification, making the heat flow asymmetric and more efficient, especially with optimized coupling parameters.

Contribution

It introduces a model with NNN interactions that significantly improves thermal rectification and its size independence in oscillator lattices.

Findings

NNN interactions increase rectification efficiency.

Maximum rectification occurs at a specific NNN coupling strength.

Performance improves with NNN interactions across parameter variations.

Abstract

In this work we study the asymmetric heat flow, i.e., thermal rectification, of a one-dimensional, mass-graded system consisting of acoupled harmonic oscillator lattice (ballistic spacer) and two diffusive leads attached to the boundaries of the former with both nearest-neighbor and next-nearest-neighbor (NNN) interactions. The latter enhance the rectification properties of the system and specially its independence on system size. The system presents a maximum rectification efficiency for a very precise value of the parameter that controls the coupling strength of the NNN interactions that depend on the temperature range wherein the device operates. The origin of this maximum value is the asymmetric local heat flow response corresponding to the NNN contribution at both sides of the lighter mass-loaded diffusive lead as quantified by the spectral properties. Upon variation of the system's parameters the performance of the device is always enhanced in the presence of NNN interactions.