Theoretical study of stability and superconductivity of ScHn (n=4–8) at high pressure

Shifeng Qian; Xiaowei Sheng; Xiaozhen Yan; Yangmei Chen; Bo Song

doi:10.1103/PhysRevB.96.094513

← Back to search

Theoretical study of stability and superconductivity of ScHn (n=4–8) at high pressure

Shifeng Qian, Xiaowei Sheng, Xiaozhen Yan, Yangmei Chen, Bo Song

DOI 10.1103/PhysRevB.96.094513 · Physical Review B

T1

Active bibliographic source — not scientific approval

Bibliographic access preserves source history; it does not approve extracted materials or validate reported claims. Review warnings on each occurrence separately.

Abstract

The synthesis of hydrogen sulfides, with the potential of high-temperature superconductivity, was recently proposed at high Tc = 203 K. It motivated us to employ an ab initio approach for the predictions of crystal structures to find the stable scandium hydrides. In addition to the earlier predicted three stoichiometries of ScH, ScH2, and ScH3, we identify three other metallic stoichiometries of ScH4, ScH6, and ScH8, which show superconductivity at significantly higher temperatures. The phases of ScH4 and ScH6, whose stability does not require extremely high pressures (<150 GPa with ZPE), are primarily ionic compounds containing exotic quasimolecular H2 arrangements. The present electron-phonon calculations revealed the superconductive potential of ScH4 and ScH6 with estimated Tc of 98 K and 129 K at 200 GPa and 130 GPa, respectively. The superconductivity of ScHn stems from the large electron-phonon coupling associated with the wagging, bending, and intermediate-frequency modes attributed mainly to the hydrogen atoms.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
ScH4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	98	200 GPa	unknown
ScH6 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	129	130 GPa	unknown
H2S Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	203	Pressure not reported	unknown
SiH4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	166	Pressure not reported	unknown
Si2H6 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	20	Pressure not reported	unknown
GeH4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	64	Pressure not reported	unknown
SiH4(H2)2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	100	Pressure not reported	unknown
CaH6 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	235	Pressure not reported	unknown
YH6 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	264	Pressure not reported	unknown
ScH2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	38.11	30 GPa	unknown
YH10 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	326	250 GPa	unknown
YH3 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	40	Pressure not reported	unknown