Coexistence of Superconductivity and Superionicity in Li$_2$MgH$_{16}$

Haoran Chen; Junren Shi

doi:10.1103/physrevb.109.l140505

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arXiv · 2305.04875

Coexistence of Superconductivity and Superionicity in Li$_2$MgH$_{16}$

Haoran Chen·Junren Shi

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Abstract

We study superconductivity in the superionic phase of the clathrate hydride Li$_2$MgH$_{16}$, where hydrogen ions diffuse among the lattice formed by lithium and magnesium ions. By employing the stochastic path-integral approach, we non-perturbatively take into account the effects of quantum diffusion and anharmonic vibrations. Our calculations reveal strong electron-ion coupling ($\lambda(0)$ = 3.7) and a high superconducting transition temperature ($T_c$) of 277 K under 260 GPa, at which the material is still superionic. $T_c$ is significantly suppressed compared with the result $T_c$ = 473 K obtained from the conventional approach based on the harmonic approximation. Our study, based on a first-principles approach applicable to superionic systems, indicates that the superconductivity and superionicity can coexist in Li$_2$MgH$_{16}$.

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Haoran Chen, Junren Shi. 2023-05-08. Coexistence of Superconductivity and Superionicity in Li$_2$MgH$_{16}$. https://doi.org/10.1103/physrevb.109.l140505

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