We have measured temperature dependence of thermoelectric power (TEP) on MgB$_2$ superconductor under hydrostatic pressure. The sign and temperature dependence of TEP shows metallic hole carriers are dominant with activation type contribution at higher temperature. TEP increases with pressure while $T_c$ decrease with ratio -0.136 K/kbar. The data are discussed in consideration of carriers from different bands and anisotropy of compressibility.
Categories: cond-mat.str-el cond-mat.supr-con