Abstract
We report the discovery of superconductivity in () synthesized by high-pressure method. is isostructural to (space group ) but with stronger spin-orbit coupling (SOC). Different from the with metallic nature, the resistivity of the normal state of shows a nonmetallic behavior. A specific-heat jump of and gap energy of are observed, which are much larger than that of (2.1 and 4.03) and the expectation of Bardeen-Cooper-Schrieffer theory (1.43 and 3.52). However, the Sommerfeld coefficient of is less than half of that of its Mo counterpart, and the specific heat above 2 K shows a power-law divergence following rather than an exponential relation. Theoretical calculations show that the Fermi surface of is dominated by W- electrons and the inclusion of SOC significantly changes its band structure, density of states, and Fermi surface topology. The realization of superconductivity by replacing Mo toward provides a candidate for the search of potential triplet superconductors with enhanced SOC.
- Received 9 July 2019
DOI:https://doi.org/10.1103/PhysRevB.100.094522
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