A topological characterization of delocalization in a spin-orbit coupling system

TL;DR

This paper introduces a topological approach using the Chern integer to characterize wavefunction delocalization in 2D electron systems with spin-orbit coupling, providing a unified framework for understanding metal-insulator transitions.

Contribution

It presents a novel topological characterization of delocalization in 2D spin-orbit coupled systems using the Chern number, linking topology to localization phenomena.

Findings

Chern number characterizes the localization-delocalization transition

The approach reproduces known transition points

Provides a unified topological framework for 2D delocalization phenomena

Abstract

We show that wavefunctions in a two-dimensional (2D) electron system with spin-orbit coupling can be characterized by a topological quantity--the Chern integer due to the existence of the intrinsic Kramers degeneracy. The localization-delocalization transition in such a system is studied in terms of such a Chern number description, which reproduces the known metal-insulator transition point. The present work suggests a unified picture for various known 2D delocalization phenomena based on the same topological characterization.