Absolute deformation potentials in semiconductors

The absolute deformation potentials (ADP's) in dielectrics depend in general on shape and surface effects, owing to the long-range nature of Coulomb interactions. We prove that, for a given direction of uniaxial strain, he ADP's of crystalline solids are well defined in terms of bulk properties in Bravais and diamond lattices, while they are not in polar lattices. We give an explicit expression for an arbitrary strain orientation and calculate them in Si and Ge using ab initio methods.