Magnetoresistance in the strongly insulating regime of GaAs two-dimensional hole systems

Abstract

Magnetoresistance (MR) of GaAs two-dimensional hole systems (2DHSs) is investigated in the strongly insulating regime. By rotating the samples, the total magnetic field B tot and the perpendicular component B ⊥ to the 2DHS are controlled independently. In the low- B ⊥ region, a large positive B ⊥ -dependence of the longitudinal resistivity ρ xx is observed when B tot is small, while it is replaced by a negative one when B tot is large. For higher B ⊥ , dips are observed in the ρ xx vs B ⊥ curve and the values of B ⊥ at the dip depend on B tot . The results are discussed both in the framework of single-particle localization and in the framework of Wigner crystallization.