ELECTRONIC-STRUCTURE OF THE RBIPT COMPOUNDS (R-EQUIVALENT-TO-Y AND YB)

The electronic structure of the semiconducting YBiPt intermetallic compound is compared with the isostructural, but metallic, YbBiPt compound. The difference in the transport properties is found to be governed by the volume, since the smaller volume in YbBiPt results in broader Yb d and Pt d bands and a closing of the semiconducting gap. The closing of the gap in YbBiPt is partly a relativistic effect, since scalar relativistic calculations do not reproduce the metallic ground state, whereas fully relativistic (Dirac) calculations do. In the semiconducting YBiPt intermetallic compound the valence band is found to be dominated by the Pt d states and the conduction band by the Y d states.