Theory of the Galvanomagnetic Properties of Magnesium and Zinc

Abstract

A theory of the galvanomagnetic properties of magnesium and zinc is developed. It is restricted to magnetic fields parallel to the hexad axis and takes into account the effects of magnetic breakdown. The transverse magnetoresistance shows the expected transition from electron-hole compensation at low fields to a noncompensated state at high fields, i.e., a transition from quadratic behavior to saturation. The Hall resistance shows the corresponding behavior. In addition, all transverse components of both conductivity and resistivity tensors show strong oscillations of the de Haas-van Alphen type due to coherent effects in the tunneling probability through small pieces of the Fermi surface. Theoretical curves are shown for various components of the galvanomagnetic tensors and compared with experimental measurements. Most parameters involved in the comparison are provided, or at least checked, by other experiments; only the breakdown field strength $H_0$ is unknown. It is found that a single $H_0$ suffices for Zn, but that for Mg, $H_0$ varies along the hexad axis. With this limited degree of adjustability, good agreement may be obtained between theory and experiment, though minor discrepancies remain unexplained.