We report a detailed study of the electronic structure of the MgB2 with different lattice constants by using the full-potential linearized augmented plane wave(FPLAPW) method. It is found that the lattice parameters have great effect on the σ band of Boron. Our results indicate that increasing lattice constant along the {\it c} axis will increase the density of states(DOS) at the Fermi level, making the σ band upward shift, and increasing hole number in the σ band. So, the superconducting transition temperature Tc will be raised correspondingly. Changing the lattice constant along {\it a} axis has an opposite effect to that of along {\it c} axis. Our result is in agreement with experiment. A possible way of searching for higher Tc superconductor has been indicated, i.e., making MgB2 to have longer {\it c} axis and shorter {\it a, b} axis by doping.
@article{arxiv.cond-mat/0104216,
title = {The band structure of MgB$_{2}$ with different lattice constants},
author = {Xiangang Wan and Jinming Dong and Hongming Weng and D. Y. Xing},
journal= {arXiv preprint arXiv:cond-mat/0104216},
year = {2009}
}