Superconductivity in non-centrosymmetric ThCoC2

作者：Grant T^*; Machado A J S; Kim D J; Fisk Z

来源：Superconductor Science and Technology, 2014, 27(3): 035004.

DOI：10.1088/0953-2048/27/3/035004

• noncentrosymmetric superconductor
• carbon-based superconductor
• ternary metal carbide
• cobalt-based superconductor

Superconductivity in compounds whose crystal structure lacks inversion symmetry are known to display intriguing properties that deviate from conventional BCS superconducting behavior. Here we report magnetization, resistivity, and heat capacity measurements on polycrystalline samples of ThCoC2, which has been reported to crystallize in the non-centrosymmetric CeNiC2 prototype structure, and show clear evidence of bulk superconductivity in ThCoC2 with a critical temperature of T-c = 2: 65 K. From the specific heat data we find a Sommerfeld coefficient of gamma = 8: 38 mJ mol(-1) K-2 and a Debye temperature of Theta(D) = 449 K. Interestingly the H-c2 superconducting phase diagram displays positive curvature, and the specific heat at low temperature deviates from conventional exponential temperature dependence, which is suggestive of possible unconventional superconducting behavior in ThCoC2, similar to that seen in the isostructural and isoelectronic non-centrosymmetric superconductor LaNiC2.

• 出版日期2014-3