Phenomenological two-gap model for the specific heat of MgB

We show that the specific heat of the superconductor 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 MgB2 is a volume effect.