Superconductivity of electron-doped chalcohydrides under high pressure

Yu Du; Zefang Wang; Hanyu Liu; Guoji Liu; Xin Zhong

doi:10.1103/PhysRevResearch.7.013049

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Superconductivity of electron-doped chalcohydrides under high pressure

Yu Du, Zefang Wang, Hanyu Liu, Guoji Liu, Xin Zhong

DOI 10.1103/PhysRevResearch.7.013049 · Physical Review Research

T1

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Abstract

As a typical representative of covalent superconductors, SH3 has emerged as a significant milestone in superconductivity history and has greatly sparked interest in compressed hydrogen-rich superconductors. Authors of previous studies on theoretical design of ternary chalcogen-hydrogen compounds (known as chalcohydrides) have mainly focused on intercalating molecular motifs into the interstitial sites of the structural lattice or substituting atoms in the SH3 backbone. Given the low electronegativity and small radius, lithium (Li) is empowered to serve as an excellent electron donor that can effectively turn the crystal structure and modulate the superconducting behavior. Here, we introduce Li into binary chalcohydrides and investigate ternary Li-M-H (M = S, Se, and Te) compounds using the state-of-the-art structure prediction method in conjunction with first-principles calculations. As a result, five stable stoichiometries, including LiSH7, Li2SH6, LiSH, Li2SH, and LiS2H, are identified at 100–200 GPa. Notably, metallic LiSH7 and Li2SH6 exhibit a layered structure where the covalent bond between sulfur and hydrogen breaks up and the hydrogen atoms are released to recombine into molecules confined into the interlayer. Furthermore, our electron-phonon simulations reveal that the estimated superconducting transition temperature (Tc) of Li2SH6 (46 K) is lower than that (77 K) of Li2SeH6 at 200 GPa, which contrasts with the general belief that the light-weight elemental compound (high Debye temperature) has higher superconductivity. Our results offer critical insights into designing high-temperature superconductors with layered structures among multinary hydrides.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
Li2SH6 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	46	200 GPa	unknown
Li2SeH6 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	77	200 GPa	unknown
LiSH7 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	12	160 GPa	unknown
H3S Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	203	200 GPa	unknown
H3Se Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	131	Pressure not reported	unknown
H4Te Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	104	Pressure not reported	unknown
LaH10 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	255	200 GPa	unknown
YH9 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	250	190 GPa	unknown
YH6 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	220	175 GPa	unknown
CaH6 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	212.5	166 GPa	unknown
LaBeH8 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	110	80 GPa	unknown
(La,Ce)H9 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	176	100 GPa	unknown
(Y,Ce)H9 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	131	114 GPa	unknown
(La,Y)H6 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	237	176 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
Mg2IrH6 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	71.5	Pressure unresolved	unknown
CSH7 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	181	100 GPa	unknown
S0.975P0.025H3 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	280	250 GPa	unknown
Be2SH3 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	29	100 GPa	unknown
SBH7 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	109	70 GPa	unknown