Thermoelectric power of MgB2-xBex -: art. no. 214534

We investigated thermoelectric power S(T) of MgB2-xBex (x=0, 0.2, 0.3, 0.4, and 0.6). S(T) decreases systematically with x, suggesting that the hole density increases. Our band calculation shows that the increase occurs in the sigma band. With the hole doping, T-c decreases. Implication of this phenomenon is discussed within the BCS framework. While the Mott formula explains only the linear part of S(T) at low temperature, incorporation of electron-phonon interaction enables us to explain S(T) over wide temperature range including the anomalous behavior at high temperature.