Magnetoresistance in Dilute $p$-Si/SiGe in Parallel and Tilted Magnetic Fields

Abstract

We report the results of an experimental study of the magnetoresistance ${\rho }_{xx}$ and ${\rho }_{xy}$ in two samples of $p$-Si/SiGe with low carrier concentrations $p$=8.2$\times 10^{10}$ cm${}^{-2}$ and $p$=2$\times 10^{11}$ 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 \textit{in-plane} magnetic field on the orbital motion of the charge carriers in the quasi-2D system. The measurements of ${\rho }_{xx}$ and ${\rho }_{xy}$ in the tilted magnetic field showed that the anomaly in ${\rho }_{xx}$, observed at filling factor $\nu$=3/2 is practically nonexistent in the conductivity ${\sigma }_{xx}$. The anomaly in ${\sigma }_{xx}$ at $\nu$=2 might be explained by overlapping of the levels with different spins 0$\uparrow$ and 1$\downarrow$ when the tilt angle of the applied magnetic field is changed. The dependence of g-factor $g^{\ast }(\Theta )/g^{\ast }(0^0)$ on the tilt angle $\Theta$ was determined.

4 pages, 6 figs, to appear in Annalen der Physik

References in corpus (2)

• Large Magnetoresistance of a Dilute $p$-Si/SiGe/Si Quantum Well in a Parallel Magnetic Field
• "Forbidden" transitions between quantum Hall and insulating phases in p-SiGe heterostructures