Low-field magnetotransport in p-type GaAs in the regime of variable-range-hopping conductivity

It is shown that phonon-assisted and activationless variable-range-hopping conduction in p-type GaAs, including transport in zero magnetic field and low-field magnetotransport, are very similar to findings in n-type GaAs previously reported. However, in p-type samples the low-field magnetoresistance is positive rather than negative. The positiveness is suggested to be a manifestation of spin-orbit scattering effects on quantum interference between nearly oriented paths containing local loops much smaller than the size of the coherence volume. The possibility to alter the nature of the paths contributing to interference by the application of a strong electric field is also discussed.