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arXiv · 1912.10941

Characterization of near-room-temperature superconductivity in yttrium superhydrides

E. F. Talantsev
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Abstract

Recently, Troyan et al (2019 arXiv:1908.01534) and Kong et al (2019 arXiv:1909.10482) extended near-room-temperature superconductors family by new yttrium superhydride polymorphs, YHn (n = 4,6,7,9), which exhibit superconducting transition temperatures in the range of Tc = 210-243 K at pressure of P = 160-255 GPa. In this paper, temperature dependent upper critical field data, Bc2(T), for highly-compressed mixture of YH4+YH6 phases (reported by Kong et al 2019 arXiv:1909.10482) is analysed to deduce the ratio of Tc to the Fermi temperature, Tf. Our analysis shows that in all considered scenarios the YH4+YH6 mixture has the ratio 0.01 < Tc/Tf < 0.04. As the result, YH4+YH6 falls in the unconventional superconductors band in the Uemura plot. It is also found that the characteristic temperature of the order parameter amplitude fluctuations, Tfluc, in the YH4+YH6 mixture is only several percent above observed Tc, and thus the superconducting transition in yttrium superhydride polymorphs is fundamentally limited by thermodynamics fluctuations.

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E. F. Talantsev. 2019-12-23. Characterization of near-room-temperature superconductivity in yttrium superhydrides. https://doi.org/10.1088/1361-6668/abb11a

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