Vortex phase dynamics in yttrium superhydride YH$_6$ at megabar pressures

A. V. Sadakov; V. A. Vlasenko; I. A. Troyan; O. A. Sobolevskiy; D. V. Semenok; Di Zhou; V. M. Pudalov

doi:10.1021/acs.jpclett.3c01577

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arXiv · 2305.06546

Vortex phase dynamics in yttrium superhydride YH$_6$ at megabar pressures

A. V. Sadakov·V. A. Vlasenko·I. A. Troyan·O. A. Sobolevskiy·D. V. Semenok·Di Zhou·V. M. Pudalov

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Abstract

A comprehensive study of the vortex phases and vortex dynamics is presented for a recently discovered high-temperature superconductor YH$_6$ with T$_C$ (onset) of 215 K under pressure of 200 GPa.Thermal activation energy (U$_0$) is derived in the framework of thermally activated flux flow (TAFF) theory. The activation energy yields a power law dependence U$_0$ $\propto$ H$^\alpha$ on magnetic field with a possible crossover at a field around 8-10 Tesla. Furthermore, we have depicted the vortex phase transition from vortex-glass to vortex-liquid state according to the vortex-glass theory. Finally, vortex phase diagram is constructed for the first time for superhydrides. Very high estimated values of flux flow barriers U$_0$(H) = 1.5-7*10$^4$ K together with high crossover fields makes YH$_6$ a rather outstanding superconductor as compared to most cuprates and iron-based systems. The Ginzburg number for YH$_6$ Gi = 3-7*10$^{-3}$ indicates that thermal fluctuations are not so strong and cannot broaden superconducting transitions in weak magnetic fields.

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A. V. Sadakov, V. A. Vlasenko, I. A. Troyan, O. A. Sobolevskiy, D. V. Semenok, Di Zhou, V. M. Pudalov. 2023-05-11. Vortex phase dynamics in yttrium superhydride YH$_6$ at megabar pressures. https://doi.org/10.1021/acs.jpclett.3c01577

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