Electronic Band Structures of f -Electron Ternary Compounds with an Energy Gap

Abstract

Recent results of APW band calculations of ThNiSn, Th3Ni3Sb4 and La3Au3Sb4 are summarized. These compounds are proper reference materials for the study of semiconductor-like property of UNiSn, U3Ni3Sb4, Ce3Au3Sb4 and Ce3Pt3Sb4. The valence bands consist of the Sn/Sb 5 p and the Ni 3d/Au 5d states. The conduction bands are derived from the Th 6d/La 5d states and are raised by the mixing between the Th 6d/La 5d state and the Ni 3d/Au 5d state. A band gap appears between the occupied valence bands and the empty conduction bands. On the basis of these results, the origin of gap formation in UNiSn, U3Ni3Sb4, Ce3Au3Sb4, Ce3Pt3Sb4 and isostructural uranium and cerium compounds is discussed.