Cooling of cryogenic electron bilayers via the Coulomb interaction

TL;DR

This paper demonstrates that Coulomb interactions between electron bilayers in silicon can serve as an effective cooling mechanism at cryogenic temperatures, surpassing phonon-based cooling methods especially at low densities.

Contribution

It introduces a novel cooling approach using Coulomb interactions in electron bilayers, providing a detailed analysis of power transfer and cooling efficiency in silicon heterostructures.

Findings

Coulomb interaction dominates phonon cooling across various conditions.

Coulomb cooling is most effective at low electron densities.

The method is relevant for spin manipulation experiments at cryogenic temperatures.

Abstract

Heat dissipation in current-carrying cryogenic nanostructures is problematic because the phonon density of states decreases strongly as energy decreases. We show that the Coulomb interaction can prove a valuable resource for carrier cooling via coupling to a nearby, cold electron reservoir. Specifically, we consider the geometry of an electron bilayer in a silicon-based heterostructure, and analyze the power transfer. We show that across a range of temperatures, separations, and sheet densities, the electron-electron interaction dominates the phonon heat-dissipation modes as the main cooling mechanism. Coulomb cooling is most effective at low densities, when phonon cooling is least effective in silicon, making it especially relevant for experiments attempting to perform coherent manipulations of single spins.