On the anomalous susceptibility of small gap magnetic semiconductors (SmS,SmSe, SmTe)

The magnetic susceptibility of the Sm chalcogenides shows a large dependence on the nature of the anion. In the three compounds (which under pressure become metallic) the energy needed to promote an electron from the 4f shell to the conduction band is very small. We present here a mechanism based on the hybridization between f states and band states that relates the anomalies of the susceptibility with the energy gaps.