Crystal structures and high-temperature superconductivity in molybdenum-hydrogen binary system under high pressure

Abstract

Motivated by advances in hydrogen-rich superconductors in the past decades, we conducted variable-composition structural searches in Mo-H binary system at high pressure. A new composition-pressure phase diagram of thermodynamically stable structures has been derived. Besides all previously discovered superconducting molybdenum hydrides, we also identified series of thermodynamically metastable superconducting structures, including I4/mmm-Mo${}_3$H${}_{14}$, I4cm-MoH${}_9$, P4/nmm-MoH${}_{10}$ and P42${}_1$2-MoH${}_{10}$, with the superconducting transition temperatures from 55 to 126 K at 300 GPa. In these superconducting molybdenum hydrides, vibrations of the Mo-atoms contributes significantly to the electron-phonon coupling and the superconducting transition temperature, in complementary to the contributions by the vibrations of the H-atoms. Our works highlight the importance of compounds with non-integer composition ratio and metastable states in material searches, for example the potential high temperature superconductors.

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Cited by in corpus (2)

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