A brief review of thermal transport in mesoscopic systems from nonequilibrium Green's function approach

TL;DR

This review discusses the application of the nonequilibrium Green's function method to study thermal and thermoelectric transport in mesoscopic systems, highlighting recent theoretical advances and diverse system analyses.

Contribution

It provides a comprehensive overview of NEGF-based approaches for phonon and thermoelectric transport in mesoscopic systems, including transient phenomena.

Findings

Phonon NEGF effectively models thermal transport in atomic chains and multi-terminal systems.

NEGF reveals thermoelectric effects involving charge, spin, and valley degrees of freedom.

Transient thermoelectric behavior can be analyzed using NEGF in partitioned schemes.

Abstract

With the rapidly increasing integration density and power density in nanoscale electronic devices, the thermal management concerning heat generation and energy harvesting becomes quite crucial. Since phonon is the major heat carrier in semiconductors, thermal transport due to phonons in mesoscopic systems has attracted much attention. In quantum transport studies, the nonequilibrium Green's function (NEGF) method is a versatile and powerful tool that has been developed for several decades. In this review, we will discuss theoretical investigations of thermal transport using the NEGF approach from two aspects. For the aspect of phonon transport, the phonon NEGF method is briefly introduced and its applications on thermal transport in mesoscopic systems including one-dimensional atomic chains, multi-terminal systems, and transient phonon transport are discussed. For the aspect of thermoelectric transport, the caloritronic effects in which the charge, spin, and valley degrees of freedom are manipulated by the temperature gradient are discussed. The time-dependent thermoelectric behavior is also presented in the transient regime within the partitioned scheme based on the NEGF method.