Electronic effect in the third-order elastic constant C456 of n-germanium

Abstract

The doping of germanium with 3×1019/cm3 arsenic atoms has been observed to change the magnitude and reverse the sign of the third-order elastic constant C456. Room-temperature measurements of the change of C456 and of the change of the shear modulus C44 upon doping are reported for two degenerate samples relative to a pure sample. By attributing these impurity effects to the electronic mechanism proposed by Keyes, the shear deformation potential constant u is found to be 17.00.2 eV, and the carrier densities of the degenerate samples are determined, in excellent agreement with the results of transport measurements. © 1965 The American Physical Society.