Terahertz quantum Hall effect in spin-split 2D heavy-hole gases

Abstract

We demonstrate that polarization-resolved THz cyclotron spectroscopy enables the transport properties of spin-split 2D heavy-holes in strained Ge quantum wells to be determined. The Rashba spin-orbit interaction strength is found from the magnetic-field dependence of the cyclotron frequencies. In high-mobility samples the optical quantum Hall effect is witnessed, where the transverse magnetoconductivity at THz frequencies exhibits plateaux. This extends the observation of the optical quantum Hall effect at terahertz frequencies to heavy-holes, and spin-split states, for the first time.