The electronic band structure ofCoS2

Abstract

Angle-resolved and energy-dependent photoemission was used to study the band structure of paramagneticCoS2 fromhigh-quality single-crystal samples. A strongly dispersing hybridized Co–S band is identified alongthe Γ–X line. Fermi level crossings are also analysed along this line, and the results areinterpreted using band structure calculations. The Fermi level crossings are very sensitiveto the separation in the S–S dimer, and it is suggested that the half-metallic gap inCoS2 may be controlled by the bonding–antibonding splitting in this dimer, rather than byexchange splitting on the Co atoms.