Magnetotransport Studies of Weak Localization and Spin-Orbit Scattering in a HgCdTe Two-Dimensional Electron Gas

Abstract

Transverse magnetoresistance and Hall effect measurements have been performed on' the two-dimensional electron gas formed in the inversion layer of H.78Cd.22Te MISFETS at low magnetic fields(<0.5 T) and at temperatures between 32 mK and 4 K. The sample fabrication included a gate structure allowing the carrier density of the 2-D system to be changed slightly more than an order of magnitude. At fixed temperatures the magnetoresistance smoothly transforms from a regime of pronounced weak localization to one of strong spin-orbit scattering with increasing carrier density. Also at low carrier densities an unusual asymmetry effect with respect to magnetic field is observed in the transverse magnetoresistance measurements. An analysis of these results is presented in view of the fact that HgCdTe system offers unique circumstances (eg. low effective mass, m*=0.006 m0, and large g-factor, g*=94) to investigate weak localization, spin orbit, and Coulomb interaction effects.