Potential parameters were developed for the simulation of MgB2 and the variations of lattice parameters and volume with pressures of up to 240GPa were calculated. The calculated results were in good agreement with experimental results below 40GPa. By using the McMillan expression, it was found that lattice stiffening dominated the behavior of the superconducting transition TC under pressure in the scope of BCS theory. Upon using the calculated Grüneisen parameter, the simulated pressure effect upon TC agreed well with experimental results. The result showed that the TC of MgB2 could be destroyed by high pressures.

The Pressure Dependence of the Structure and Superconducting Transition Temperature of MgB2. Y.Shao, X.Zhang: Journal of Physics - Condensed Matter, 2004, 16, 1103-13