Electronic structure of mixed-valence semiconductors in the LSDA+U approximation.: II.: SmB6 and YbB12 -: art. no. 165209

The electronic structure and optical spectra of SmB6 and YbB12 are investigated theoretically from first principles, using the fully relativistic Dirac LMTO band structure method. The electronic structure is obtained with the local spin-density approximation (LSDA), as well as with the so-called LSDA+U approach. The energy band structures of SmB6 and YbB12 are related to their measured XPS and UPS spectra as well as optical spectra. The LSDA+U band structure calculations produce a small hybridization energy gap in SmB6 and YbB12 for samarium and ytterbium ions in the divalent state.