Metal-Insulator Transition in a 2-Dimensional System with an Easy Spin Axis

V. Senz, U. Doetsch, U. Gennser, T. Ihn, T. Heinzel, K. Ensslin, R. Hartmann, D. Gruetzmacher

Published 1999-03-24, updated 1999-11-29Version 3

The low-temperature resistivity of a SiGe 2-dimensional hole gas has been studied using the gate controlled carrier density as a parameter. A metal-insulator transition is seen both in the temperature and in the electric field behaviour. Values of 1 for the dynamical exponent and 2.85 for the correlation length exponent are obtained from scaling plots. No quenching of the metallic phase in a parallel magnetic field is observed. Since in our system there is an easy axis for magnetization, this result supports the hypothesis that the transition is related to spin interactions.