Heat Diode Effect and Negative Differential Thermal Conductance across Nanoscale Metal-Dielectric Interfaces

TL;DR

This paper analytically investigates heat transfer across nanoscale metal-dielectric interfaces, revealing the emergence of heat diode effect and negative differential thermal conductance due to inelastic electron-phonon scattering, with implications for thermal control and energy harvesting.

Contribution

It provides a microscopic analytical model explaining heat diode and negative differential conductance effects at nanoscale interfaces, which are absent in bulk materials.

Findings

Heat diode effect observed at nanoscale interfaces.

Negative differential thermal conductance demonstrated.

Inelastic electron-phonon scattering is key to these effects.

Abstract

Controlling heat flow by phononic nanodevices has received significant attention recently because of its fundamental and practical implications. Elementary phononic devices such as thermal rectifiers, transistors, and logic gates are essentially based on two intriguing properties: heat diode effect and negative differential thermal conductance. However, little is known about these heat transfer properties across metal-dielectric interfaces, especially at nanoscale. Here we analytically resolve the microscopic mechanism of the nonequilibrium nanoscale energy transfer across metal-dielectric interfaces, where the inelastic electron-phonon scattering directly assists the energy exchange. We demonstrate the emergence of heat diode effect and negative differential thermal conductance in nanoscale interfaces and explain why these novel thermal properties are usually absent in bulk metal-dielectric interfaces. These results will generate exciting prospects for the nanoscale interfacial energy transfer, which should have important implications in designing hybrid circuits for efficient thermal control and open up potential applications in thermal energy harvesting with low-dimensional nanodevices.