Electronic structure and optical spectra of LuInCu4 and YbMCu4 (M= Cu, Ag,Au, Pd, and In)

Optical reflectivity measurements over a wide spectral range and at differe nt temperatures together with self-consistent electronic band structure cal culations have been used to investigate the electronic structure of the LuI nCu4 and YbMCu4 (M = Cu,Ag,Au,Pd,In) compounds. The electronic structure of the compounds is investigated theoretically using an energy-band approach in combination with the linear-response formalism. The energy-hand structur e is obtained within the local-spin-density approximation (LSDA) and within its extension that explicitly takes into account the on-site 4f Coulomb in teraction Lr (LSDA + U). A remarkable agreement between theory and experime nt has been found.