A detailed first-principles local-density-functional investigation was made of the structural, electronic, dynamic and superconducting properties of MgB2. In particular, Al doping was examined, as well as reduced dimensionality and pressure effects upon the electronic and superconducting properties of this compound. The ab initio calculations for the case of 50%Al doping were able to correctly reproduce the measured frequencies of the E2g phonon and explain the disappearance of superconductivity in terms of filling effects on both carrier concentration and electron–phonon coupling. The surface study shows that an enhanced density of states at the Fermi level was found in the B-terminated case. However, it was found that the Mg-terminated surface was the most stable structure over the entire range permitted by the chemical potentials; in agreement with the most recent experimental results. Study of the E2g phonon frequency under pressure was able to explain critical temperature decreased under an applied pressure.

Electronic, Dynamic and Superconducting Properties of MgB2 - Doping, Surface and Pressure Effects. G.Profeta, A.Continenza, F.Bernardini, M.Monni, S.Massidda: Superconductor Science and Technology, 2003, 16, 137-42