Magnetic field-induced giant enhancement of electron-phonon energy transfer in strongly disordered conductors

TL;DR

This paper predicts that applying a magnetic field to strongly disordered conductors significantly boosts electron-phonon energy transfer, potentially enhancing cooling power and ultrasound attenuation by up to two orders of magnitude.

Contribution

It introduces a theoretical mechanism showing magnetic fields can greatly enhance energy transfer in disordered conductors with broken time-reversal symmetry.

Findings

Cooling power can be increased by a factor of 100 at 10 Tesla in 2D InSb films.

Enhanced ultrasound attenuation is also predicted under magnetic fields.

The effect is due to slowed relaxation of soft modes caused by disorder and magnetic field.

Abstract

Relaxation of soft modes (e.g. charge density in gated semiconductor heterostructures, spin density in the presence of magnetic field) slowed down by disorder may lead to giant enhancement of energy transfer (cooling power) between overheated electrons and phonons at low bath temperature. We show that in strongly disordered systems with time-reversal symmetry broken by external or intrinsic exchange magnetic field the cooling power can be greatly enhanced. The enhancement factor as large as $10^{2}$ at magnetic field $B \sim 10$ Tesla in 2D {\rm InSb} films is predicted. A similar enhancement is found for the ultrasound attenuation.