Topological quantization of the spin Hall effect in two-dimensional paramagnetic semiconductors

TL;DR

This paper introduces models of 2D paramagnetic semiconductors where the intrinsic spin Hall effect is precisely quantized, linking bulk topological invariants to edge states and demonstrating the effect through spin accumulation.

Contribution

It presents exactly quantized spin Hall effect models in 2D paramagnetic semiconductors, connecting topological bulk properties with edge state phenomena.

Findings

Quantized spin Hall effect in proposed models

Bulk topological charge determines edge states

Explicit demonstration via spin accumulation

Abstract

We propose models of two dimensional paramagnetic semiconductors where the intrinsic spin Hall effect is exactly quantized in integer units of a topological charge. The model describes a topological insulator in the bulk, and a "holographic metal" at the edge, where the number of extended edge states crossing the Fermi level is dictated by (exactly equal to) the bulk topological charge. We also demonstrate the spin Hall effect explicitly in terms of the spin accumulation caused by the adiabatic flux insertion.