Semimetallic behaviour of SmS at high pressure

Abstract The transition from semiconducting to metallic intermediate-valence behaviour occurring at 20 kbar in SmS in studied by resistivity and Hall coefficient measurements (1.2 K ⪕ T ⪕300 K, 4 kbar ⪕ P ⪕21 kbar). The data are analyzed in a two-band-conduction model. It is concluded that an indirect band gap closes at 20 kbar and that a direct one subsist above this transition.