title: On the origin of a band gap in compounds of diamond-like structures.
abstract: Electronic structure calculations were performed to examine the origin of a band gap present in most 18-electron half-Heusler compounds and its absence in NaTl. In these compounds of diamond-like structures, the presence or absence of a band gap is controlled by the sigma antibonding between the valence s orbitals, and the bonding characteristics of the late-main-group elements depend on the extent of their ns/np hybridization. Implications of these observations on the formal oxidation state and the covalent bonding of the transition-metal atoms in 18-electron half-Heusler and related compounds were discussed.
authors.affiliation: Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany. j.koehler@ fkf.mpg.de
authors.forename: Jürgen
authors.initials: J
authors.lastname: Köhler
authors.forename: Shuiquan
authors.initials: S
authors.lastname: Deng
authors.forename: Changhoon
authors.initials: C
authors.lastname: Lee
authors.forename: Myung-Hwan
authors.initials: MH
authors.lastname: Whangbo