Comment on Anisotropic s-wave superconductivity in MgB2

[摘要] An analytical result for the renormalization of the jump of the heat capacity DeltaC/C-N by the anisotropy of the order parameter is derived in the framework of the model proposed by Haas and Maki [Phys. Rev. B 65, 020502(R) (2001)], for both prolate and oblate anisotropy. The graph of DeltaC/C-N versus the ratio of the gaps on the equator and the pole of the Fermi surface, Delta(e)/Delta(p), allows a direct determination of the gap anisotropy parameter Delta(e)/Delta(p) using data from specific-heat measurements.