Limitation of electron mobility from hyperfine interaction in ultra-clean quantum wells and topological insulators

TL;DR

This paper investigates how nuclear spin fluctuations cause electron scattering, limiting mobility in quantum wells and topological insulators, highlighting an intrinsic scattering mechanism affecting electron transport.

Contribution

It introduces a detailed calculation of electron momentum relaxation due to hyperfine interactions, emphasizing the role of nuclear spin correlations in limiting mobility.

Findings

Nuclear spin fluctuations significantly reduce electron mobility.

Hyperfine interaction causes backscattering of Dirac fermions.

Electron scattering depends on nuclear spin spatial correlations.

Abstract

The study of electron transport and scattering processes limiting electron mobility in high-quality semiconductor structures is central to solid-state electronics. Here, we uncover an unavoidable source of electron scattering which is caused by fluctuations of nuclear spins. We calculate the momentum relaxation time of electrons in quantum wells governed by the hyperfine interaction between electrons and nuclei and show that this time drastically depends on the spatial correlation of nuclear spins. Moreover, the scattering processes accompanied by a spin flip are a source of the backscattering of Dirac fermions at conducting surfaces of topological insulators.