Superconducting properties of MgB2 from first principles

• Autor(a) principal: Floris, A.
• Data de Publicação: 2007
• Outros Autores: Sanna, A., Lüders, M., Profeta, G., Lathiotakis, N. N., Marques, M. A. L., Franchini, C., Gross, E. K. U., Continenza, A., Massidda, S.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10316/4376; https://doi.org/10.1103/PhysRevLett.94.037004
• topic: Superconductivity

The discovery of superconductivity in MgB2, with a rather high transition temperature, has triggered a large number of theoretical and experimental investigations on important issues such as, e.g., the role of gap anisotropy over the Fermi surface (multi-gap superconductivity). We report here the results obtained in this compound using the density functional theory for superconductors, recently proposed by the authors. Without invoking any adjustable parameters, such as [mu]*, we obtain the transition temperature, the gaps, and the specific heat in very good agreement with experiment. Moreover, our calculations allow for a detailed study of how the phonon-mediated attraction and Coulomb repulsion act differently on [sigma] and [pi] states, thereby stabilizing the observed superconducting phase.