Upper critical magnetic field in superconducting Dirac semimetal

Abstract

Temperature dependence of the upper critical field Hc2 of the Dirac semi -metal (DSM) with phonon mediated pairing is considered within semi -classical approximation. The low temperature dependence deviates from conventional BCS superconductor with parabolic dispersion relation 1 even for large adiabaticity parameter, γ = µ/ ( Ω)., where µ is the chemical potential and Ω -Debye frequency. In particular the "reduced field", ratio of zero temperature Hc2 to derivative at critical temperature, h * = Hc2 (0) / −T dH c2 dT |T c , depends on γ and can be extended beyond the adiabatic limit. The reduced magnetic field ratio is universal (independent of the chemical potential, interaction strength etc.) and smaller than the Werthamer ratio for clean superconductors: h * = 0.55 for DSM, h * (0) = 0.69 for parabolic band. The results are in good agreement compared with recent experiments on T aP . arXiv:1809.01863v1 [cond-mat.supr-con]

Angular dependence of the upper critical field in the high-pressure 1T′ phase of MoTe2

“…Together with the semimetallic nature of MoTe 2 , the enhancement of α can probably be traced back to the low E F and high m * . Another possible scenario is that the suppression of H c2 could be attributed by the multiband effect with large tunneling between the valleys in Dirac and Weyl semimetals, according to the recent calculation 49 . We now assess the anisotropy of the superconductivity in the 1T phase via a full angular dependence of the upper critical field H c2 (θ) at selected temperatures between 30 mK (0.008T c ) and 2.2 K (0.61T c ), as illustrated in Fig.…”

Aslamazov Larkin Conductivity in Weyl Semimetals

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