Unusual anisotropy of inplane field magnetoresistance in ultra-high mobility SiGe/Si/SiGe quantum wells

摘要

We find an unusual anisotropy of the inplane field magnetoresistance inultra-high mobility SiGe/Si/SiGe quantum wells. The anisotropy depends on theorientation between the inplane field, $B_\parallel$, and current, $I$,relative to the crystallographic axes of the sample and is a consequence of theintrinsic ridges on the quantum well surface. For the simplest orientationsbetween current and crystallographic axes, a method of recalculating themagnetoresistance measured at $I\perp B_\parallel$ into the one measured at$I\parallel B_\parallel$ is suggested and is shown to yield results that agreewith the experiment.