Conduction band-phonon coupling in I.V. materials

Intermediate valence materials are very sensitive to lattice strains. In this paper a study is made of the effect on the conduction bands of a strain having the symmetry of a zone boundary longitudinal mode directed along a four-fold axis in SmB6. The conduction band is distorted, a rearrangement of conduction electrons occurs and also a transfer from the localised levels. There is an energy lowering proportional to the square of the strain, which manifests itself as a decrease of the phonon frequency. Estimates suggest the effect is far from negligible. (Auth.)