Thermodynamic and transport properties of SmS under high pressure

We measured transport and thermodynamic properties of the valence-fluctuating phase of SmS up to 8.5 kbar, and found a bump structure in the temperature dependence of the electrical resistivity and a Schottky-type anomaly in the temperature dependence of the thermal expansion coefficient at a characteristic temperature T(0). We also observed that the absolute value of the Hall constant rapidly increases below T(0). From these results, we argue that the steep rise of the electrical resistivity below To is inherent to golden SmS and can be ascribed to the decrease in the carrier concentration possibly due to the pseudo gap formation. (C) 2009 Elsevier B.V. All rights reserved.