Pressure-induced high−Tc superconductivity in the ternary clathrate system Y-Ca-H

Wendi Zhao; Defang Duan; Mingyang Du; Xianxiang Yao; Zihao Huo; Qiwen Jiang; Tian Cui

doi:10.1103/PhysRevB.106.014521

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Pressure-induced high−Tc superconductivity in the ternary clathrate system Y-Ca-H

Wendi Zhao, Defang Duan, Mingyang Du, Xianxiang Yao, Zihao Huo, Qiwen Jiang, Tian Cui

DOI 10.1103/PhysRevB.106.014521 · Physical Review B

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Abstract

The hydrogen-rich ternary compounds under high pressure which rely on the synergistic effect of crystal structure and electronic property changes have a good prospect of realizing room temperature superconductivity. Here, we study the structure and superconductivity of the ternary Y-Ca-H system under high pressure using abinitio calculations. We found four unprecedented ternary hydrides with clathrate hydrogen sublattice: P−3m1−YCa2H18, Fm−3m−Y3CaH24, P4/mmm−YCaH20, and Fm−3m−YCa3H24 which are potential high-temperature superconductors. Strikingly, the superconducting transition temperature of Y3CaH24 was calculated to be 242–258 K at 150 GPa. The strong electron-phonon coupling and the high electron density of states of hydrogen at the Fermi level play important roles in high-temperature superconductivity. Further analysis suggests that the phonon softening in the mid-frequency region induced by Fermi surface nesting effectively enhances the electron-phonon coupling. We found that the appropriate stoichiometric ratio is crucial for the discovery of new hydrides in the Y-Ca-H system, which would provide ideas for exploring ternary hydrides.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
Y3CaH24 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	258	150 GPa	unknown
YCaH12 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	230	180 GPa	unknown
YCaH12 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	258	200 GPa	unknown
H3S Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	200	155 GPa	unknown
LaH10 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	260	180 GPa	unknown
HfH10 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	234	250 GPa	unknown
Li2MgH16 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	473	250 GPa	unknown
LaBeH8 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	185	20 GPa	unknown
CaH6 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	235	150 GPa	unknown
YH6 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	264	120 GPa	unknown
YH10 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	303	400 GPa	unknown
CaH10 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	220	500 GPa	unknown