The electrical resistivity, Hall coefficient, and weak-field magnetoresistance of homogeneous single crystals of n-type Mg2Ge have been measured. The samples were either Al-doped or undoped, and had exhaustion carrier concentrations from 1.3 X 10 16 cm-3 to 8.2 X 1017 cm-3 . The electrical resistivity and Hall coefficient were measured from 4.2 K to 300 K. Impurity band conduction was observed at the lower temperatures. The Hall mobility from 150 K to 300 K had a T -3/2 temperature dependence which indicates that Intravalley acoustic mode scattering Is the dominant scattering mechanism in this temperature range. From a consideration of the selection rules and this Hall mobility temperature dependence, we conclude that the symmetry of the conduction band minima is X, rather than X.. The weak-field magneto-resistance of Mg2Ge, which was measured at 77.4 K and at three other stable temperatures (4.36 K, 14.5 K and 299.5 K), was found to be much smaller than the magnetoresistance of Ge and Mg2Sn. The magneto-resistance coefficients b, c, and d were obtained from these measurements and found to satisfy the symmetry relations b + c + d » 0, d < 0. This result confirms the theoretical prediction that n-type Mg2Ge Is a many-valley semiconductor with constant energy spheroids In the ﹤100﹥ directions. The anlsotropy parameter K was between 1.51 and 1.78 at 77 K. Inhomogeneous samples showed anomalies In the Hall mobilities and in the magnetoresistances.
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