The insulator-metal transition volumes for BaS, BaSe, and BaTe are calculated for the first time, using the self-consistent augmented-spherical-wave technique. The metallization transition volumes are smaller than those corresponding to the NaCl→CsCl structural transitions, but 10-15% larger than those obtained by the Herzfeld dielectric theory. The calculated equilibrium energy gaps in the NaCl structure underestimate the measured ones by 50-60%.

• Received 7 November 1983

DOI:https://doi.org/10.1103/PhysRevB.29.5836