Verification of Anisotropic s-Wave Superconducting Gap Structure in CeRu2 from Low-Temperature Field-Angle-Resolved Specific Heat Measurements

Abstract

The field-angle-resolved specific heat C(T,H,phi) of the f-electron superconductor CeRu2 (Tc=6.3 K) has been measured at low temperatures down to 90 mK on two single crystals of slightly different qualities. We reveal that the C(phi) oscillation in a rotating magnetic field, originating from the gap anisotropy, diminishes at low temperatures below the characteristic field H*, as expected for an anisotropic gap without nodes. We also observe the suppression of H* by decreasing the gap anisotropy ratio ${\Delta }_{\min }/{\Delta }_{\max }$, a behavior that has been predicted from a microscopic theory for anisotropic s-wave superconductors. The present technique is established as a powerful tool for investigating minimum-gap structures as well as nodal structures.

arXiv comment5 pages, 5 figures

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Cited by in corpus (7)

• Classification of multipole superconductivity in multi-orbital systems and its implications
• Evidence for chiral d-wave superconductivity in URu2Si2 from the field-angle variation of its specific heat
• Gap structure of FeSe determined by field-angle-resolved specific heat measurements
• Variational cluster approach to s-wave pairing in heavy-fermion superconductors
• Anisotropic Fully-Gapped Superconductivity Possibly Mediated by Charge Fluctuations in a Nondimeric Organic Complex
• Disorder-sensitive node-like small gap in FeSe
• Local spectroscopic evidence for a nodeless magnetic kagome superconductor CeRu${}_2$