Thermoelectric power of nickel and ytterbium at high pressure: a comparative study

The thermoelectric power (TEP) of Ni and Yb have been investigated up to 10 and 7 GPa, respectively, with a new laser-heated diamond anvil cell technique. Ni exhibits free electron-like behavior that can be explained by the Mott expression for thermopower. A small decrease in the TEP is observed in the pressure range 2–3 GPa. There are variations in the TEP of Yb as a function of pressure that correlate with previously observed structural phase transitions. The increase in TEP of Yb in the metallic bcc phase is understood from the increase in the Hubbard coulomb correlation energy.