Weak anti-localization in spin-orbit coupled lattice systems

TL;DR

This paper investigates weak anti-localization phenomena in spin-orbit coupled lattice systems using a two-dimensional Wolff Hamiltonian, revealing unique mechanisms and a crossover to weak localization influenced by Fermi energy and band gap changes.

Contribution

It introduces a novel understanding of WAL in SOC lattices, highlighting the role of interband SOC effects and the crossover behavior, differing from conventional WAL in metals.

Findings

WAL arises in SOC lattices with distinct mechanisms from metals.

Interband SOC effects contribute significantly to WAL.

A crossover from WAL to weak localization occurs with changes in Fermi energy or band gap.

Abstract

The quantum correction to electrical conductivity is studied on the basis of two-dimensional Wolff Hamiltonian, which is an effective model for a spin-orbit coupled (SOC) lattice system. It is shown that weak anti-localization (WAL) arises in SOC lattices, although its mechanism and properties are different from the conventional WAL in normal metals with SOC impurities. The interband SOC effect induces the contribution from the interband singlet Cooperon, which plays a crucial role for WAL in the SOC lattice. It is also shown that there is a crossover from WAL to weak localization in SOC lattices when the Fermi energy or band gap changes. The implications of the present results to Bi-Sb alloys and PbTe under pressure are discussed.