We show that the specific heat of the superconductor MgB_2 (MgB2) in zero field, for which significant non-BCS features have been reported, can be fitted, essentially within experimental error, over the entire range of temperature to T_c by a phenomenological two-gap model. The resulting gap parameters agree with previous determinations from band-structure calculations, and from various spectroscopic experiments. The determination from specific heat, a bulk property, shows that the presence of two superconducting gaps in MgB_2 is a volume effect.
@article{arxiv.cond-mat/0107196,
title = {Phenomenological two-gap model for the specific heat of MgB_2},
author = {F. Bouquet and Y. Wang and R. A. Fisher and D. G. Hinks and J. D. Jorgensen and A. Junod and N. E. Phillips},
journal= {arXiv preprint arXiv:cond-mat/0107196},
year = {2009}
}
Comments
7 pages, 4 figures Accepted for publication in Europhysics Letters Text is unchanged. Figure 1 was made clearer (labels). We tried to update cond-mat references from the bibliography which were published (before october 5th)