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A simple theory of 40 K superconductivity in MgB2: first-principles calculations of Tc, its dependence on boron mass and pressure |
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| Authors: | T. Yildirim,O. Gü lseren |
| Affiliation: | a NIST Center for Neutron Research, National Institute of Standards and Technology, Building 235, Room E112, Gaithersburg, MD 20899, USA b Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA |
| Abstract: | We have studied the superconducting properties of MgB2 from first-principles under isotropic, uniaxial, and biaxial compressions. We find that the in-plane boron phonons near the zone-center are very anharmonic and strongly coupled to the planar B σ bands near the Fermi level. This mode is found to be the key to quantitatively explain the observed high Tc, the total isotope effect and the pressure dependence of Tc. We propose that a stringent test on the hole and phonon based theories of the superconductivity in MgB2 would be a measurement of the biaxial ab-compression dependence of Tc. |
| Keywords: | 74.25.Kc 63.20.Ry 63.20.Kr 61.12.&minus q 74.25.Jb |
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