The variation of the superconducting critical temperature as a function of the pressure, P, in MgB2 was studied within the framework of 2-band Eliashberg theory and a traditional phonon-coupling mechanism. The 2-band Eliashberg equations were solved by using first-principles calculations with simple assumptions for the variation, with pressure, of the relevant physical quantities. It was found that the experimental TC versus P curve could be fitted very well, and that information could be obtained on the dependence of the electron–phonon interaction matrix <I2> upon pressure. The pressure-dependence of the superconductive gaps, Δσ and Δπ, was also predicted.

Pressure Dependence of Critical Temperature in MgB2 and Two-Bands Eliashberg Theory. G.A.Ummarino: Physica C, 2005, 423[3-4], 96-102