Localization and electron-electron interaction effects in magnetoresistance of p-type Ge/Ge_{1-x}Si_x heterostructures

Yu. G. Arapov, G. I. Harus, V. N. Neverov, A. T. Lonchakov, N. G. Shelushinina, M. V. Yakunin

Published 2002-12-27Version 1

We report on the results of investigation the conductivity and magnetoresistance (MR) temperature dependencies for the two strained multilayer p-type Ge/Ge_{1-x}Si_x heterostructures. The usual logarithmic temperature dependencies for zero magnetic field conductivity due to the weak localization (WL) and electron- electron interaction (EEI) effects take place in both samples. For one of the samples the negative MR is observed in a whole range of magnetic fields up to ~1T at T <=12K, but for the other sample the MR transforms from the negative to positive at B >= 0.2T and T >=1.3K. We attribute such a behavior to the interplay of two types of holes due to partial filling of the second subband. Extrapolation of the observed high-field parabolic MR to B = 0 allows to separate WL and EEI contributions to the total quantum corrections to conductivity at B = 0 resulting for both of our structures in that EEI part is ~2/3 and the WL part is ~1/3.