Quantum Spin Hall Effect

TL;DR

This work predicts a quantized spin Hall effect in the absence of any magnetic field, where the intrinsic spin Hall conductance is quantized in units of 2(e/4pi).

Abstract

The quantum Hall liquid is a novel state of matter with profound emergent properties such as fractional charge and statistics. Existence of the quantum Hall effect requires breaking of the time reversal symmetry caused by an external magnetic field. In this work, we predict a quantized spin Hall effect in the absence of any magnetic field, where the intrinsic spin Hall conductance is quantized in units of $2 \frac{e}{4π}$. The degenerate quantum Landau levels are created by the spin-orbit coupling in conventional semiconductors in the presence of a strain gradient. This new state of matter has many profound correlated properties described by a topological field theory.

Figures (1)

• Figure 1: Spin up and down electrons have opposite chirality as they feel the opposite spin-orbit coupling force. Total charge conductance vanishes but spin conductance is quantized. The inset shows the lattice displacement leading to the strain configuration.