Possible multiband superconductivity in the quaternary carbide YRe2SiC. (14th May 2021) - R De Faria, L
Abstract: We report for the first time the occurrence of superconductivity in the quaternary silicide carbide YRe2 SiC with T c ≍ 5.9 K. The emergence of superconductivity was confirmed by means of magnetic susceptibility, electrical resistivity, and heat capacity measurements. The presence of a well-developed heat capacity feature at T c confirms that superconductivity is a bulk phenomenon, while a second feature in the heat capacity near 0.5 T c combined with the unusual temperature dependence of the upper critical field H c2 ( T ) indicate the presence of a multiband superconducting state. Additionally, the linear dependence of the lower critical field H c1 with temperature resemble the behavior found in compounds with unconventional pairing symmetry. Band structure calculations reveal that YRe2 SiC could harbor a non-trivial topological state and that the low-energy states occupy multiple disconnected sheets at the Fermi surface, with different degrees of hybridization, nesting, and screening effects, therefore making unconventional multiband superconductivity plausible.