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In the last years, the search for high critical-temperature superconductors has focused on metal and molecular hydrides, which may exhibit superconductivity at room temperature under very high pressures [1]. Actually, such behavior has been suggested by N. W. Ashcroft in 1968, since hydrogen-based materials possess elevated vibrational frequencies, as a consequence of the low atomic mass of hydrogen [2].
In this work, we present a self-consistent solution of the Eliashberg equations [3], in contrast to the widely used McMillan-Allen-Dynes parameterized one [4], where effects of the electron-phonon coupling, the density of states at the Fermi level and characteristic phonon frequencies are further analyzed. Finally, these two solutions are comparatively applied to several metal hydride superconductors, whose results are additionally contrasted with their measured critical temperatures.
This work was partially supported by research projects CONAHCYT-CF-2023-I-830, UNAM-IN110823 and LANCAD-UNAM-DGTIC-039. T.E. acknowledges the master’s fellowship from CONAHCYT of Mexico.
[1] A. P. Drozdov, M. I. Eremets, I. A. Troyan, V. Ksenofontov and S. I. Shylin, Conventional superconductivity at 203 Kelvin at high pressures in the sulfur hydride system, Nature 525, 73-76 (2015).
[2] N. W. Ashcroft, Metallic hydrogen: A high-temperature superconductor? Phys. Rev. Lett. 21 (26), 1748-1749 (1968).
[3] G. M. Eliashberg, Interactions between electrons and lattice vibrations in a superconductor, Soviet Phys. JEPT 11 (3), 696-702 (1960).
[4] P. B. Allen and R. C. Dynes, Transition temperature of strong-coupled superconductors reanalyzed, Phys. Rev. B 12 (3), 905-922 (1975).
