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Kacmarcik, J., Pribulova, Z., Marcenat, C., Klein, T., Rodiere, P., Cario, L. & Samuely, P. (2010) Specific heat measurements of a superconducting NbS2 single crystal in an external magnetic field: Energy gap structure. Phys. Rev. B, 82 014518.
Added by: Laurent Cournède (2016-03-10 21:37:32) |
| Type de référence: Article DOI: 10.1103/PhysRevB.82.014518 Numéro d'identification (ISBN etc.): 1098-0121 Clé BibTeX: Kacmarcik2010a Voir tous les détails bibliographiques  |
Catégories: PMN Mots-clés: 2h-nbse2, dependent superconductivity, intercalation Créateurs: Cario, Kacmarcik, Klein, Marcenat, Pribulova, Rodiere, Samuely Collection: Phys. Rev. B |
Consultations : 1/523
Indice de consultation : 4% Indice de popularité : 1% |
| Résumé |
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The heat capacity of a 2H-NbS2 single crystal has been measured by a highly sensitive ac technique down to 0.6 K and in magnetic fields up to 14 T. At very low temperatures, data show excitations over an energy gap (2 Delta(S)/k(B)T(c)approximate to 2.1) much smaller than the BCS value. The overall temperature dependence of the electronic specific heat C-e can be explained either by the existence of a strongly anisotropic single-energy gap or within a two-gap scenario with the large gap about twice bigger than the small one. The field dependence of the Sommerfeld coefficient gamma shows a strong curvature for both principal-field orientations, parallel (H parallel to c) and perpendicular (H perpendicular to c) to the c axis of the crystal, resulting in a magnetic field dependence of the superconducting anisotropy. These features are discussed in comparison to the case of MgB2 and to the data obtained by scanning-tunneling spectroscopy. We conclude that the two-gap scenario better describes the gap structure of NbS2 than the anisotropic s-wave model.
Added by: Laurent Cournède |