Superconductivity of MgB2: covalent bonds driven metallic.

نویسندگان

  • J M An
  • W E Pickett
چکیده

A series of calculations on MgB2 and related isoelectronic systems indicates that the layer of Mg2+ ions lowers the nonbonding B pi ( p(z)) bands relative to the bonding sigma ( sp(x)p(y)) bands compared to graphite, causing sigma-->pi charge transfer and sigma band doping of 0.13 holes/cell. Because of their two dimensionality the sigma bands contribute strongly to the Fermi level density of states. Calculated deformation potentials of gamma point phonons identify the B bond stretching modes as dominating the electron-phonon coupling. Superconductivity driven by sigma band holes is consistent with the report of destruction of superconductivity by doping with Al.

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عنوان ژورنال:
  • Physical review letters

دوره 86 19  شماره 

صفحات  -

تاریخ انتشار 2001