Transverse Magnetoresistance inn-Type Germanium

The transverse magnetoresistance and Hall coefficient in high-resistivity $n$-type germanium were measured in pulsed magnetic fields up to 175 kG at temperatures between 20 and 70°K. The magnetoresistance ratio was roughly proportional to $H{T}^{-1.2\mathrm{}}$ for fields above 100 kG and temperatures below 40°K for two orientations: H in the [111] direction, and H in the [110] direction with I in the [$1\overline{1}0$] direction. It was proportional to $H^{1.2}{T}^{-1.5\mathrm{}}$ for H in the [001] direction. The Hall coefficient increased with $H$ at temperatures below 20°K for H in the [001] direction and, to a lesser extent, for H in the [111] direction. This is attributed to a decrease in the conduction-band electron density due to a change in the ionization energy. Calculations by Minner predict such a decrease for H in the [001] direction but no decrease for H in the [111] direction.