Superhydrides on the way to ambient pressure: weak localization and persistent X-ray photoconductivity in BaSiH$_{8}$

Fuente: arXiv
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Autores principales: Semenok, Dmitrii V., Zhou, Di, Luther, Sven, Helm, Toni, Kadobayashi, Hirokazu, Nakamoto, Yuki, Shimizu, Katsuya, Pervakov, Kirill S., Sadakov, Andrei V., Sobolevskiy, Oleg A., Pudalov, Vladimir M., Di Cataldo, Simone, Lucrezi, Roman, Boeri, Lilia, Galasso, Michele, Alabarse, Frederico G., Troyan, Ivan A., Struzhkin, Viktor V.
Formato: Preprint
Publicado: 2026
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author Semenok, Dmitrii V.
Zhou, Di
Luther, Sven
Helm, Toni
Kadobayashi, Hirokazu
Nakamoto, Yuki
Shimizu, Katsuya
Pervakov, Kirill S.
Sadakov, Andrei V.
Sobolevskiy, Oleg A.
Pudalov, Vladimir M.
Di Cataldo, Simone
Lucrezi, Roman
Boeri, Lilia
Galasso, Michele
Alabarse, Frederico G.
Troyan, Ivan A.
Struzhkin, Viktor V.
author_facet Semenok, Dmitrii V.
Zhou, Di
Luther, Sven
Helm, Toni
Kadobayashi, Hirokazu
Nakamoto, Yuki
Shimizu, Katsuya
Pervakov, Kirill S.
Sadakov, Andrei V.
Sobolevskiy, Oleg A.
Pudalov, Vladimir M.
Di Cataldo, Simone
Lucrezi, Roman
Boeri, Lilia
Galasso, Michele
Alabarse, Frederico G.
Troyan, Ivan A.
Struzhkin, Viktor V.
contents Reducing the stabilization pressure of superhydrides represents one of the most important challenges in hydrogen-saturated compound chemistry. Moving in this direction, we studied the Ba-Si-H system at 0-142 GPa using transport measurements, 1H nuclear magnetic resonance, single-crystal and powder X-ray diffraction in the temperature range of 4-317 K. We synthesized the previously predicted cubic BaSiH$_{8}$ at pressures of 18-31 GPa. Remarkably, we demonstrate that BaSiH$_8$ remains stable upon decompression to ambient conditions and can be recovered from the diamond anvil cell. Obtained Ba-Si polyhydrides exhibit metallic and superconducting properties ($\textit{T$_c$}$ = 9 K, $\textit{B$_{c2}$}$(0)=13-16 T) at 142 GPa. However, at pressures below 50 GPa, these hydrides behave as degenerate semiconductors (bandgap < 0.4 meV) or poor metals with weak electron localization, negative magnetoresistance, photovoltaic effect, and persistent photoconductivity in the X-ray and visible range. Our work demonstrates the high-pressure synthesis of Ba-Si polyhydrides that remain stable upon decompression to ambient conditions, overcoming a critical bottleneck in superhydride chemistry and establishing a foundation for practical applications in hydrogen storage.
format Preprint
id arxiv_https___arxiv_org_abs_2603_14051
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Superhydrides on the way to ambient pressure: weak localization and persistent X-ray photoconductivity in BaSiH$_{8}$
Semenok, Dmitrii V.
Zhou, Di
Luther, Sven
Helm, Toni
Kadobayashi, Hirokazu
Nakamoto, Yuki
Shimizu, Katsuya
Pervakov, Kirill S.
Sadakov, Andrei V.
Sobolevskiy, Oleg A.
Pudalov, Vladimir M.
Di Cataldo, Simone
Lucrezi, Roman
Boeri, Lilia
Galasso, Michele
Alabarse, Frederico G.
Troyan, Ivan A.
Struzhkin, Viktor V.
Superconductivity
Materials Science
Reducing the stabilization pressure of superhydrides represents one of the most important challenges in hydrogen-saturated compound chemistry. Moving in this direction, we studied the Ba-Si-H system at 0-142 GPa using transport measurements, 1H nuclear magnetic resonance, single-crystal and powder X-ray diffraction in the temperature range of 4-317 K. We synthesized the previously predicted cubic BaSiH$_{8}$ at pressures of 18-31 GPa. Remarkably, we demonstrate that BaSiH$_8$ remains stable upon decompression to ambient conditions and can be recovered from the diamond anvil cell. Obtained Ba-Si polyhydrides exhibit metallic and superconducting properties ($\textit{T$_c$}$ = 9 K, $\textit{B$_{c2}$}$(0)=13-16 T) at 142 GPa. However, at pressures below 50 GPa, these hydrides behave as degenerate semiconductors (bandgap < 0.4 meV) or poor metals with weak electron localization, negative magnetoresistance, photovoltaic effect, and persistent photoconductivity in the X-ray and visible range. Our work demonstrates the high-pressure synthesis of Ba-Si polyhydrides that remain stable upon decompression to ambient conditions, overcoming a critical bottleneck in superhydride chemistry and establishing a foundation for practical applications in hydrogen storage.
title Superhydrides on the way to ambient pressure: weak localization and persistent X-ray photoconductivity in BaSiH$_{8}$
topic Superconductivity
Materials Science
url https://arxiv.org/abs/2603.14051