Magnetic Susceptibility of Germanium

The magnetic susceptibility of highly doped germanium has been measured between 300°K and 1.3°K. The contribution of the carriers to the susceptibility has been derived from the data. Most of the measurements concern electrons occupying unbound states in the conduction band. The observed conduction-electron susceptibility has been compared with theoretical estimates based on the effective-mass values given by cyclotron-resonance experiments. Our results support a 4-ellipsoid model of $n$-Ge. No appreciable change in the effective masses is observed between room temperature and 1.3°K. We find no evidence for any substantial change in the curvature of the conduction band for energies up to 0.08 ev above the band minimum. This finding contradicts certain conclusions of Stevens et al. An explanation for the disagreement is proposed.