Subband structure and magneto-conductivity of InAs-MIS inversion layers

We have investigated magneto-transport in an inversion layer of InAs. At low perpendicular magnetic fields, we observed negative magneto-conductivity due to the spin-orbit interaction. The negative B perpendicular to-dependence of conductivity vanishes in a strong parallel magnetic field. The magneto-conductivity in the parallel magnetic field (B perpendicular to = 0) is negative at low-magnetic fields, but it turns to positive at 1-2 T. While the electron-concentration dependence suggests that the positive magneto-conductivity is related to the subband structure, the present theory cannot explain the positive magneto-conductivity. (C) 2003 Elsevier B.V. All rights reserved.