We report first-principles calculations of the electronic band structure and lattice dynamics for the new superconductor MgB2. The excellent agreement between theory and our inelastic neutron scattering measurements of the phonon density of states gives confidence that the calculations provide a sound description of the physical properties of the system. The numerical results reveal that the in-plane boron phonons (with E2g symmetry) near the zone-center are very anharmonic, and are strongly coupled to the partially occupied planar B σ bands near the Fermi level. This giant anharmonicity and non-linear electron-phonon coupling is key to explaining the observed high Tc and boron isotope effect in MgB2
@article{arxiv.cond-mat/0103469,
title = {Giant anharmonicity and non-linear electron-phonon coupling in MgB$_{2}$; A combined first-principles calculations and neutron scattering study},
author = {T. Yildirim and O. Gulseren and J. W. Lynn and C. M. Brown and T. J. Udovic and H. Z. Qing and N. Rogado and K. A. Regan and M. A. Hayward and J. S. Slusky and T. He and M. K. Haas and P. Khalifah and K. Inumaru and R. J. Cava},
journal= {arXiv preprint arXiv:cond-mat/0103469},
year = {2009}
}
Comments
In this revised version (to appear in PRL) we also discuss the boron isotope effect. Please visit http://www.ncnr.nist.gov/staff/taner/mgb2 for details