Experimental evidence for a two-gap structure of superconducting NbSe2: A specific-heat study in external magnetic fields

C. L. Huang; J.-Y. Lin; Y. T. Chang; C. P. Sun; H. Y. Shen; C. C. Chou; H. Berger; T. K. Lee; H. D. Yang

doi:10.1103/PhysRevB.76.212504

← Back to search

Experimental evidence for a two-gap structure of superconducting NbSe2: A specific-heat study in external magnetic fields

C. L. Huang, J.-Y. Lin, Y. T. Chang, C. P. Sun, H. Y. Shen, C. C. Chou, H. Berger, T. K. Lee, H. D. Yang

DOI 10.1103/PhysRevB.76.212504 · Physical Review B

T1

Active bibliographic source — not scientific approval

Bibliographic access preserves source history; it does not approve extracted materials or validate reported claims. Review warnings on each occurrence separately.

Abstract

To resolve the discrepancies of the superconducting order parameter in quasi-two-dimensional NbSe2, comprehensive specific-heat measurements have been carried out. By analyzing both the zero-field and mixed-state data with magnetic fields perpendicular (H⊥c) to and parallel (H∥c) to the c axis of the crystal and using the two-gap model, we conclude that (1) more than one energy scale of the order parameter is required for superconducting NbSe2 due to the thermodynamic consistency; (2) ΔL=1.26meV and ΔS=0.73meV are obtained; (3) NS(0)∕N(0)=11%–20%; (4) the observation of the kink in γ(H) curve suggests that the two-gap scenario is more favorable than the anisotropic s-wave model to describe the gap structure of NbSe2; and (5) ΔS is more isotropic and has a three-dimensional-like feature and is located either on the Se or the bonding Nb Fermi sheets.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
NbSe2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	6.7	Pressure not reported	unknown