Quantum spin Hall effect in two-dimensional metals without spin-orbit coupling*

The quantum spin Hall effect (QSHE) has been observed in topological insulators using spin-orbit coupling (SOC) as the probe, but it has not yet been observed in a metal. We propose an experiment to measure the QSHE of an electron or hole in a two-dimensional (2D) metal without SOC. Through the inner radius of a 2D metallic Corbino disk lies a long solenoid, and a radial charge current is applied between the inner and outer disk radii, thereby inducing a uniform fixed potential differentce across those radii. By combining changes in the flux in the solenoid and in the potential difference, spontaneous quantized azimuthal currents that can depend upon the particle's spin are generated.