Ultrafast electronic heat dissipation through surface-to-bulk Coulomb coupling in quantum materials

TL;DR

This paper introduces a theory of Coulomb-based near-field radiative heat transfer that enables ultrafast electronic cooling in quantum materials, surpassing phonon-mediated processes and achieving sub-picosecond timescales.

Contribution

It develops a theoretical framework for Coulomb cooling via surface-to-bulk Coulomb coupling, highlighting its efficiency and potential to outperform traditional phonon cooling in quantum materials.

Findings

Coulomb cooling can reach sub-picosecond timescales.

It can dominate over phonon-mediated cooling under certain conditions.

The theory applies to topological insulators and graphene near small-gap materials.

Abstract

The timescale of electronic cooling is an important parameter controlling the performance of devices based on quantum materials for optoelectronic, thermoelectric and thermal management applications. In most conventional materials, cooling proceeds via the emission of phonons, a relatively slow process that can bottleneck the carrier relaxation dynamics, thus degrading the device performance. Here we present the theory of near-field radiative heat transfer, that occurs when a two-dimensional electron system is coupled via the non-retarded Coulomb interaction to a three-dimensional bulk that can behave as a very efficient electronic heat sink. We apply our theory to study the cooling dynamics of surface states of three dimensional topological insulators, and of graphene in proximity to small-gap bulk materials. The ``Coulomb cooling'' we introduce is alternative to the conventional phonon-mediated cooling, can be very efficient and dominate the cooling dynamics under certain circumstances. We show that this cooling mechanism can lead to a sub-picosecond time scale, significantly faster than the cooling dynamics normally observed in Dirac materials.