Piezoresistance and Magnetoresistance in Impurity Conduction of Germanium

Abstract

The effect of uniaxial compression along [111] on impurity conduction has been investigated in n-type germanium with intermediate concentration and with different compensation ratios. Activation energy of resistivity for compensated samples of antimony-doped germanium does not change with stress and is determined by the spacial configuration of impurities and by the extent of wave function derived from one valley.
Magnetoresistance has been measured as a function of stress. Temperature dependence and anisotropy of positive magnetoresistance can be interpreted as modification of wave functions by a magnetic field. Negative magnetoresistance has been observed in most samples used and shows large anisotropy under stress. In the case of p-type germanium, which shows no negative magnetoresistance without stress, negative magnetoresistance is also observed under [100] compression.