Thermal rectification in three-dimensional mass-graded anharmonic oscillator lattices

Abstract

In this work we perform a systematic analysis of various structural parameters that have influence on the thermal rectification effect, i.e. asymmetrical heat flow, and the negative differential thermal resistance -reduction of the heat flux as the applied thermal bias is increased-present in a one-dimensional, segmented mass-graded system consisting of a coupled nearest-neighbor harmonic oscillator lattice (ballistic spacer) and two diffusive leads (modeled by a substrate potential) attached to the lattice at both boundaries. At variance with previous works, we consider the size of the spacer as smaller than that of the leads. Also considered is the case where the leads are connected along the whole length of the oscillator lattice; that is, in the absence of the ballistic spacer. Upon variation of the system's parameters it was determined that the performance of the device, as quantified by the spectral properties, is largely enhanced in the absence of the ballistic spacer for the small system-size limit herein considered.

Advances of phononics in 2012–2022

“…(a) Thermal rectification r vs. system width W for lateral lengths of N = 16 (circles), 32 (triangles), 64 (diamonds), and 128 (squares) with M max = 10, M max is the mass of any oscillator in the leftmost. [38] (b) Diagram of the model based on two harmonic oscillators (Two masses are coupled to each other through a spring constant k. Each mass is harmonically trapped and connected to a bath characterized by its temperature T i and its friction coefficient γ i ). [39] (c) A thermal rectifier based on an N = 5-bead harmonic chain.…”

“…To further optimize the parameters, Bastida et al [38] extended the study to a 3D mass-graded anharmonic lattice of length N and width W . The lattice site n is expressed as (n 1, n 2 , n 3 ), where n 1 = n 2 = 1, .…”