# Noncentrosymmetric superconductor with a bulk three-dimensional Dirac cone gapped by strong spin-orbit coupling

## Author(s): Ali, Mazhar N; Gibson, Quinn D; Klimczuk, T; Cava, Robert J

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 Abstract: The layered, noncentrosymmetric heavy element PbTaSe2 is found to be superconducting. We report its electronic properties accompanied by electronic-structure calculations. Specific heat, electrical resistivity, and magnetic-susceptibility measurements indicate that PbTaSe2 is a moderately coupled, type-II BCS superconductor (Tc = 3.72 K, Ginzburg–Landau parameter κ = 17) with an electron-phonon coupling constant of λep = 0.74. Electronic-structure calculations reveal a single bulk three-dimensional Dirac cone at the K point of the Brillouin zone derived exclusively from its hexagonal Pb layer; it is similar to the feature found in graphene except there is a 0.8 eV gap opened by spin-orbit coupling. The combination of large spin-orbit coupling and lack of inversion symmetry also results in large Rashba splitting on the order of tenths of an eV. Publication Date: Jan-2014 Electronic Publication Date: 14-Jan-2014 Citation: Ali, Mazhar N, Gibson, Quinn D, Klimczuk, T, Cava, RJ. (2014). Noncentrosymmetric superconductor with a bulk three-dimensional Dirac cone gapped by strong spin-orbit coupling. Physical Review B, 89 (2), 10.1103/PhysRevB.89.020505 DOI: doi:10.1103/PhysRevB.89.020505 ISSN: 1098-0121 EISSN: 1550-235X Pages: 020505-1 - 020505-5 Type of Material: Journal Article Journal/Proceeding Title: Physical Review B Version: Final published version. Article is made available in OAR by the publisher's permission or policy.