Magnetic-field-induced phase transitions in a Si/SiGe hole system

We have performed low-temperature transport experiments on a Si/SiGe hole system. The measured transverse and longitudinal conductivities σxy and σxx allow us to study the magnetic-field-induced transitions in this system. In particular, we present the study of 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(B), and σxy(B) which corresponds to a boundary of the quantum phase transition.