Metallic behavior in p-SiGe quantum wells

Abstract

In the following we discuss the metallic behavior observed in p-SiGe quantum wells [167]. Magnetotransport data taken across the MIT will be analyzed. Interference corrections to the conductivity are extracted from weak-localization studies at low magnetic fields and interaction corrections to the conductivity in the diffusive regime are obtained from the temperature dependence of the Hall resistivity, similar to Ref. [159]. In addition, following the suggestion in Ref. [123], we compare the remaining (Drude) part of the conductivity with the theory for temperature dependent screening suitable for the system [122]. Using this program we arrive at the following conclusions: (I) In the metallic regime the 2D-hole gas in our SiGe samples behaves like an ordinary Fermi liquid and exhibits localizing interference and interaction corrections to the conductivity that can be well described by conventional theory. We find empirically that the concept of a Fermi liquid describes the data taken at large r _s ≈ 6. (II) The metallic temperature dependence of the resistivity can be quantitatively described by the theory of temperature-dependent screening, which can be incorporated in the Drude part of the resistivity.