Effects of pressure on the superconducting properties of magnesium diboride

We discuss the effects of hydrostatic pressure on the superconducting properties of MgB 2 within the framework of the Eliashberg theory. By considering the pressure dependences of all parameters appearing in the McMillan formula, we show that the calculated pressure derivative of T c as well as the variation of T c with pressure are in good agreement with recent measurements. The pressure dependences of the energy gap Δ 0 , the effective interaction strength N(E F )v, the critical magnetic field H c (0), and the electronic specific-heat coefficient γ are also predicted for this system. A comparison of the pressure effects in nontransition elements clearly suggests that MgB 2 is an electron-phonon-mediated superconductor.