Deformation Potentials of Lead Telluride

Abstract

A computer calculation of the important deformation potentials of PbTe was made. The calculation was based on an extension of the augmented-plane-wave method. Group theory was extensively used in connection with the reduction of the cubic group of this material by a uniaxial strain. The calculated pressure coefficient of the energy gap is in excellent agreement with experiment. This fact confirms that the highest valence band is an ${L_1}^{+}$ state at the edge of the Brillouin zone, along the (111) direction. The calculated coefficients for shear strain do not agree with the numbers derived from experimental work. Here, it is felt that incomplete models were assumed in the analysis of the experiments. In particular, it is suggested that the intravalley one-phonon acoustical model for scattering of carriers is inadequate for lead telluride.