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

Abstract

We have performed low-temperature transport experiments on a Si/SiGe hole system. The measured transverse and longitudinal condductivities $σ_{xx}$ and $σ_{xy}$ 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 &#34;anomalous Hall insulator&#34; regime near a Landau level filling factor $ν=1.5$. The &#34;anomalous&#34; 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 $ρ_{xx} (B)$, $ρ_{xy} (B)$, $σ_{xx}$, and $σ_{xy}$ which corresponds to a boundary of the quantum phase transition.