The Isotope Effect and Critical Magnetic Fields of Superconducting YH${}_6$: A Migdal-Eliashberg Theory Approach

Abstract

The emergence of near-ambient temperature superconductivity under pressure in the metal hydride systems has motivated a desire to further understand such remarkable properties, specifically critical magnetic fields. YH${}_6$ is suggested to be a departure from conventional superconductivity, due to apparent anomalous behavior. Using density functional calculations in conjunction with Migdal-Eliashberg theory we show that in YH${}_6$ the critical temperature and the isotope effect under pressure, as well as the high critical fields, are consistent with strong-coupling conventional superconductivity; a property anticipated to extend to other related systems. Furthermore, the strong-coupling corrections occur to the expected BCS values for the Ginzburg-Landau parameter (${\kappa }_1(T)$), London penetration depth (${\lambda }_L(T)$), electromagnetic coherence length ($\xi (T)$), and the energy gap (${\Delta }_0$).

6 pages, 3 figures, 1 table

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