Anomalous high-temperature superconductivity in YH$_6$
Abstract
Pressure-stabilized hydrides are a new rapidly growing class of high-temperature superconductors which is believed to be described within the conventional phonon-mediated mechanism of coupling. Here we report the synthesis of yttrium hexahydride Im3m-YH that demonstrates the superconducting transition with T = 224 K at 166 GPa, much lower than the theoretically predicted (>270 K). The measured upper critical magnetic field B(0) of YH was found to be 116-158 T, which is 2-2.5 times larger than the calculated value. A pronounced shift of T in yttrium deuteride YD with the isotope coefficient 0.4 supports the phonon-assisted superconductivity. Current-voltage measurements showed that the critical current I and its density J may exceed 1.75 A and 3500 A/mm at 0 K, respectively, which is comparable with the parameters of commercial superconductors, such as NbTi and YBCO. The superconducting density functional theory (SCDFT) and anharmonic calculations suggest unusually large impact of the Coulomb repulsion in this compound. The results indicate notable departures of the superconducting properties of the discovered YH from the conventional Migdal-Eliashberg and Bardeen-Cooper-Schrieffer theories.
Cite
@article{arxiv.1908.01534,
title = {Anomalous high-temperature superconductivity in YH$_6$},
author = {Ivan A. Troyan and Dmitrii V. Semenok and Alexander G. Kvashnin and Andrey V. Sadakov and Oleg A. Sobolevskiy and Vladimir M. Pudalov and Anna G. Ivanova and Vitali B. Prakapenka and Eran Greenberg and Alexander G. Gavriliuk and Viktor V. Struzhkin and Aitor Bergara and Ion Errea and Raffaello Bianco and Matteo Calandra and Francesco Mauri and Lorenzo Monacelli and Ryosuke Akashi and Artem R. Oganov},
journal= {arXiv preprint arXiv:1908.01534},
year = {2021}
}
Comments
arXiv admin note: text overlap with arXiv:1902.10206