Thermoelectric power of cerium at high pressures

Abstract

The electronic phase transition in cerium occurring near 7 kbar pressure at room temperature which is attributed to the 4f–5d electron promotion has been studied using thermoelectric power as a tool. The important results that have emerged out of this work are: (α) the relatively large variation in the absolute thermoelectric power of γ-cerium (normal fcc phase) with pressure prior to the phase transition (in contrast to the rather small resistivity change with pressure in this region); (b) a sharp decrease in the thermoelectric power accompanying the iso-structural γ-α phase transition; and (c) the continuous decrease in the thermoelectric power of α-cerium (collapsed fcc phase) with pressure, ultimately changing sign at higher pressures. An explanation based on the "virtual bound state" model is proposed to account for these results.