Comment on “Anisotropic s-wave superconductivity: Comparison with experiments on ” by A. I. Posazhennikova et al.
Laboratorium voor Vaste-Stoffysica en Magnetisme,
Katholieke Universiteit Leuven
Celestijnenlaan 200 D, B-3001 Leuven, Belgium
2 Department of Theoretical Physics, Faculty of Physics, Sofia University “St. Kliment Ohridski” - 5 J. Bourchier Blvd., Bg-1164 Sofia, Bulgaria
Accepted: 13 December 2002
An analytical result for the renormalization of the jump of the heat capacity by the anisotropy of the order parameter is derived within the framework of the very recent model proposed by Posazhennikova, Dahm and Maki (Europhys. Lett., 60 (2002) 134), for both oblate and prolate anisotropy. The graph of vs. the ratio of the gaps on the equator and the pole of the Fermi surface, , allows a direct determination of the gap anisotropy parameter by fitting data from specific-heat measurements . Using the experimental value by Wang, Plackowski, and Junod (Physica C 355 (2001) 179) we find .
PACS: 74.20.Rp – Pairing symmetries (other than s-wave) / 74.25.Bt – Thermodynamic properties / 74.70.-b – Superconducting materials (excluding high- compounds)
© EDP Sciences, 2003