Magnetoresistance in dilute p-Si/SiGe in parallel and tilted magnetic fields

Abstract

We report the results of an experimental study of the magnetoresistance ρxx and ρxy in two samples of p-Si/SiGe with low carrier concentrations p=8.2×10 10 cm −2 and p=2×10 11 cm −2 . The research was performed in the temperature range of 0.3-2 K and in the magnetic fields of up to 18 T, parallel or tilted with respect to the two-dimensional (2D) channel plane. The large in-plane magnetoresistance can be explained by the influence of the in-plane magnetic field on the orbital motion of the charge carriers in the quasi-2D system. The measurements of ρxx and ρxy in the tilted magnetic field showed that the anomaly in ρxx, observed at filling factor ν=3/2 is practically nonexistent in the conductivity σxx. The anomaly in σxx at ν=2 might be explained by overlapping of the levels with different spins 0↑ and 1↓ when the tilt angle of the applied magnetic field is changed. The dependence of g-factor g * (Θ)/g * (0 0 ) on the tilt angle Θ was determined.

Stand alone experimental setup for dc transport measurements

“…While decent results were obtained on Ge:Mn ͑Ref. 4͒ and Si/SiGe, 5 it was found that that setup was suitable for short term ͑about 30-60 min long͒ experiments only. During longtime experiments the triggering cycle sometimes failed, and the added nanovoltmeter performed incorrect measurements.…”