Field Dependence of Electronic Specific Heat in Two-Band Superconductors

摘要

The vortex structure is studied in light of MgB_2 theoretically based on a two-band superconducting model by means of Bogoliubov-de Gennes framework. The field dependence of the electronic specific heat coefficient γ(H) is focused. The exponent α H~α is shown to become smaller by adjusting the gap ratio of the two gaps on the major and minor bands. The observed extremely small value α ～ 0.23 could be reasonable in this two-band model with the gap ratio ～0.3.