Weak antilocalization beyond the fully diffusive regime in Pb1-xSnxSe topological quantum wells

TL;DR

This study investigates weak antilocalization in Pb1-xSnxSe topological quantum wells in a regime where the elastic scattering length exceeds the magnetic length, revealing limitations of traditional models and the influence of non-carrier-dependent scattering channels.

Contribution

The paper demonstrates weak antilocalization beyond the fully diffusive regime in topological quantum wells and applies a new model to analyze coherence time in this regime.

Findings

Elastic scattering length exceeds 100nm

Hikami-Larkin-Nagaoka model is invalid in this regime

Coherence time limited by non-carrier-dependent scattering channels

Abstract

We report the measurements and analysis of weak antilocalization (WAL) in Pb1-xSnxSe topological quantum wells in a new regime where the elastic scattering length is larger than the magnetic length. We achieve this regime through the development of high-quality epitaxy and doping of topological crystalline insulator (TCI) quantum wells. We obtain elastic scattering lengths that exceeds 100nm and become comparable to the magnetic length. In this transport regime, the Hikami-Larkin-Nagaoka model is no longer valid. We employ the model of Wittmann and Schmid to extract the coherence time from the magnetoresistance. We find that despite our improved transport characteristics, the coherence time may be limited by scattering channels that are not strongly carrier dependent, such as electron-phonon or defect scattering.