Abstract Hydrogen–rich materials are expected to become high–temperature superconductors after their metallization at pressures considerably lower than pure hydrogen. Combined with light elements Li and B, a high–pressure orthorhombic stable LiBH2 phase at 150 GPa is proposed by using CALYPSO and ab initio calculations. oS16-LiBH2 may be a highly plausible intermediate phase involved in dehydriding Pnma-LiBH4. Meanwhile, oS16-LiBH2 turns its semiconductor into a conducting property within the pressure range of 150 to 200 GPa and exhibits stronger conductivity along with an increasing pressure. Our electron–phonon coupling calculations reveal the softening of transverse acoustic mode B 3 u enhances the superconductivity of oS16-LiBH2 above 300 GPa, and its λ and T c values increase to 1.15 and 10 K under 600 GPa, respectively. Furthermore, when the pressure exceeds 700 GPa, the B 3 u phonon softening makes oS16-LiBH2 dynamically unstable. Pressure–induced phonon softening may effectively improve the superconducting properties of hydrides within a certain pressure range.

中文翻译：

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超高压下正交LiBH2相压力诱导金属化和超导性的从头算研究

摘要 富氢材料在远低于纯氢的压力下金属化后有望成为高温超导体。结合轻元素 Li 和 B，使用 CALYPSO 和 ab initio 计算提出了 150 GPa 的高压正交稳定 LiBH2 相。oS16-LiBH2 可能是参与 Pnma-LiBH4 脱水的高度可信的中间相。同时，oS16-LiBH2 在 150 至 200 GPa 的压力范围内将其半导体转变为导电性能，并随着压力的增加表现出更强的导电性。我们的电子-声子耦合计算表明，横向声学模式 B 3 u 的软化增强了 oS16-LiBH2 在 300 GPa 以上的超导性，其 λ 和 T c 值在 60​​0 GPa 下分别增加到 1.15 和 10 K。此外，当压力超过 700 GPa 时，B 3 u 声子软化使 oS16-LiBH2 动态不稳定。压力诱导的声子软化可以在一定压力范围内有效改善氢化物的超导性能。