2001/11/09 by Hyoung Joon Choi, Choi, Hyoung Joon, David Roundy +7
Materials Science · Physics and Astronomy · #Boron and Carbon Nanomaterials Research #Physics of Superconductivity and Magnetism #Superconductivity in MgB2 and Alloys #cond-mat.supr-con
paper · pdf · doi:10.48550/arxiv.cond-mat/0111183
13 pages, 4 figures
arxiv created 2001/11/09 · arxiv updated 2009/11/30
We report first-principles calculations of the k- and T-dependent superconducting gap Delta(k,T) in MgB2 and its manifestation in various measured quantities. Because the Fermi surface has disconnected sheets with different electron-phonon coupling strengths, our calculations show that near T=0, the values of Delta(k) cluster into two groups: large values (about 6.5 to 7.5 meV) on the strongly coupled sheets and small values (about 1 to 3 meV) on the weakly coupled sheets. The calculated gap, quasiparticle density of states, and specific heat and their temperature dependences are in agreement with the recent measurements which conclude that MgB2 is a multiple gap superconductor. In fact, theory predicts four prominent values for the gap at low T.