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 σ-band. With the hole-doping, Tc 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.
@article{arxiv.cond-mat/0202457,
title = {Thermoelectric power of MgB$_{2-x}$Be$_x$},
author = {J. S. Ahn and E. S. Choi and W. Kang and D. J. Singh and E. J. Choi},
journal= {arXiv preprint arXiv:cond-mat/0202457},
year = {2009}
}