Superconductivity of Bi-III phase of elemental bismuth: Insights from muon-spin rotation and density functional theory

Article

关键词: TEMPERATURE-DEPENDENCE;    POINT-CONTACT;    PRESSURE;    BEHAVIOR;    GAP;    TRANSITION;    ACCURATE;    VANADIUM;    MGB2;    SN;   

DOI  :  10.1103/PhysRevB.98.140504

来源: SCIE

【 摘 要 】

Using muon-spin rotation the pressure-induced superconductivity in the Bi-III phase of elemental bismuth (transition temperature T-c similar or equal to 7.05 K) was investigated. A Ginzburg-Landau parameter kappa = lambda/xi = 30(6) (lambda is the magnetic penetration depth, xi is the coherence length) was estimated, which turns out to be the highest among known single element superconductors. The temperature dependence of the superconducting energy gap [Delta(T)] reconstructed from lambda(-2)(T) deviates from the weakly coupled BCS prediction. The coupling strength 2 Delta/k(B)T(c) similar or equal to 4.34 was estimated, thus implying that Bi-III stays within the strong-coupling regime. The density functional theory calculations suggest that superconductivity in Bi-III could be described within the Eliashberg approach with a characteristic phonon frequency omega(1n) similar or equal to 5.5 meV. An alternative pairing mechanism to the electron-phonon coupling involves the possibility of Cooper pairing induced by Fermi-surface nesting.

【 授权许可】

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