High-temperature superconductivity in hydrides

Abstract

Over the past six years (2015-2021), many superconducting hydrides with\ncritical temperatures $T_{C}$ up to 250 K, which are currently record highs,\nhave been discovered. Now we can already say that a special field of\nsuperconductivity has developed. This is hydride superconductivity at ultrahigh\npressures. For the most part, the properties of superhydrides are well\ndescribed by the Migdal-Eliashberg theory of strong electron-phonon\ninteraction, especially when anharmonicity of phonons is taken into account.\nThe isotope effect, the effect of the magnetic field (up to 60-70 T) on the\ncritical temperature and critical current in the hydride samples, the\ndependence of $T_{C}$ on the pressure and degree of doping were investigated.\nThe divergences between the theory and experiment are of interest, especially\nin the field of phase stability and in the behavior of the upper critical\nmagnetic fields at low temperatures. This article presents a retrospective\nanalysis of data of 2015-2021 and describes promising directions for future\nresearch of hydride superconductivity.\n