Superconductivity of Metallic Boron in MgB₂

Authors

J. Kortus, Georgetown University, Washington, D.C.
I.I. Mazin, Naval Research Laboratory, Washington, D.C.
Kirill D. Belashchenko, University of Nebraska-LincolnFollow
Vladimir P. Antropov, Ames Laboratory, US Department fo EnergyFollow
L.L. Boyer, Naval Research Laboratory, Washington, D.C.

Date of this Version

5-14-2001

Comments

Published in PHYSICAL REVIEW LETTERS VOLUME 86, NUMBER 20. © 2001 The American Physical Society. Used by permission.

Abstract

Boron in MgB₂ forms stacks of honeycomb layers with magnesium as a space filler. Band structure calculations indicate that Mg is substantially ionized, and the bands at the Fermi level derive mainly from B orbitals. Strong bonding with an ionic component and considerable metallic density of states yield a sizable electron-phonon coupling. Together with high phonon frequencies, which we estimate via zone-center frozen phonon calculations to be between 300 and 700 cm^-1, this produces a high critical temperature, consistent with recent experiments. Thus MgB₂ can be viewed as an analog of the long sought, but still hypothetical, superconducting metallic hydrogen.