Studies of the Temperature-Driven Flow Lines and Phase Transitions in a Two-Dimensional Si/SiGe Hole System

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We have performed low-temperature transport experiments on a Si/SiGe hole system. The measured transverse and longitudinal condductivities σxx and σxy allow us to study the magnetic-field-induced transitions in the system. In particular, we present the first study of the temperature-driven flow lines in the "anomalous Hall insulator" regime near a Landau level filling factor ν=1.5. The "anomalous" temperature-driven flow lines could be due to the unusual energy level scheme in a Si/SiGe hole system. Moreover, for 3<ν<5, there is a temperature-independent point in ρxx (B), ρxy (B), σxx, and σxy which corresponds to a boundary of the quantum phase transition.