Ternary superhydrides under pressure of Anderson's theorem: Near-record superconductivity in (La,Sc)H$_{12}$

Dmitrii V. Semenok; Ivan A. Troyan; Di Zhou; Andrei V. Sadakov; Kirill S. Pervakov; Oleg A. Sobolevskiy; Anna G. Ivanova; Michele Galasso; Frederico Gil Alabarse; Wuhao Chen; Chuanying Xi; Toni Helm; Sven Luther; Vladimir M. Pudalov; Viktor V. Struzhkin

doi:10.1002/adfm.202504748

arXiv · 2408.07477

Ternary superhydrides under pressure of Anderson's theorem: Near-record superconductivity in (La,Sc)H$_{12}$

Dmitrii V. Semenok·Ivan A. Troyan·Di Zhou·Andrei V. Sadakov·Kirill S. Pervakov·Oleg A. Sobolevskiy·Anna G. Ivanova·Michele Galasso·Frederico Gil Alabarse·Wuhao Chen·Chuanying Xi·Toni Helm·Sven Luther·Vladimir M. Pudalov·Viktor V. Struzhkin

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Abstract

Lanthanum-hydrogen system and its derivatives remain among the most promising for achieving room-temperature superconductivity. In this study, we examined the formation of ternary lanthanum-scandium superhydrides at pressures up to 220 GPa. The primary product of the LaSc alloy's reaction with hydrogen is newly discovered cubic (La,Sc)H$_{12}$, demonstrating clear superconducting transition in all six channels of the van der Pauw scheme below 244-248 K. In this compound with an unusually large unit cell volume, virtually no magnetoresistance was observed in fields up to 68 Tesla. Synthesized samples of (La,Sc)H$_{12}$ demonstrate pronounced superconducting diode and SQUID-like effects at a record high temperature of 233 K. Furthermore, our analysis revealed the formation of lower hexagonal polyhydrides (La,Sc)H$_{6-7}$, which could potentially account for the anomaly in electrical resistance observed near 274 K. This anomaly between 265-290 K also appears in the radio-frequency transmission measurements and may be of a superconducting nature.

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Dmitrii V. Semenok, Ivan A. Troyan, Di Zhou, Andrei V. Sadakov, Kirill S. Pervakov, Oleg A. Sobolevskiy, Anna G. Ivanova, Michele Galasso, Frederico Gil Alabarse, Wuhao Chen, Chuanying Xi, Toni Helm, Sven Luther, Vladimir M. Pudalov, Viktor V. Struzhkin. 2024-08-14. Ternary superhydrides under pressure of Anderson's theorem: Near-record superconductivity in (La,Sc)H$_{12}$. https://doi.org/10.1002/adfm.202504748

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