Superconductivity with strong electron-phonon coupling in noncentrosymmetric W3Al2C

T. P. Ying, Y. P. Qi, and H. Hosono
Phys. Rev. B 100, 094522 – Published 18 September 2019

Abstract

We report the discovery of superconductivity in W3Al2C (Tc=7.6K) synthesized by high-pressure method. W3Al2C is isostructural to Mo3Al2C (space group P4132) but with stronger spin-orbit coupling (SOC). Different from the Mo3Al2C with metallic nature, the resistivity of the normal state of W3Al2C shows a nonmetallic behavior. A specific-heat jump of ΔCes/γTc=2.7 and gap energy of 2Δ(0)/γTc=5.43 are observed, which are much larger than that of Mo3Al2C (2.1 and 4.03) and the expectation of Bardeen-Cooper-Schrieffer theory (1.43 and 3.52). However, the Sommerfeld coefficient of W3Al2C is less than half of that of its Mo counterpart, and the specific heat above 2 K shows a power-law divergence following Ces/γTc(T/Tc)3.3 rather than an exponential relation. Theoretical calculations show that the Fermi surface of W3Al2C is dominated by W-5d electrons and the inclusion of SOC significantly changes its band structure, density of states, and Fermi surface topology. The realization of superconductivity by replacing 4d Mo toward 5dW provides a candidate for the search of potential triplet superconductors with enhanced SOC.

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  • Received 9 July 2019

DOI:https://doi.org/10.1103/PhysRevB.100.094522

©2019 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

T. P. Ying1, Y. P. Qi2,*, and H. Hosono1,†

  • 1Materials Research Center for Element Strategy, Tokyo Institute of Technology, Yokohama 226-8503, Japan
  • 2School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China

  • *qiyp@shanghaitech.edu.cn
  • hosono@mces.titech.ac.jp

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Issue

Vol. 100, Iss. 9 — 1 September 2019

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