Same-group element replacement enhances superconductivity in clathrate-like YH4

Xuejie Li; Yuzhou Hao; Yujie Liu; Xiaoying Wang; Turab Lookman; Jun Sun; Xiangdong Ding; Zhibin Gao

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arXiv · 2509.17501

Same-group element replacement enhances superconductivity in clathrate-like YH4

Xuejie Li·Yuzhou Hao·Yujie Liu·Xiaoying Wang·Turab Lookman·Jun Sun·Xiangdong Ding·Zhibin Gao

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Abstract

H3S, LaH10, and hydrogen-based compounds have garnered significant interest due to their high-temperature superconducting properties. However, the requirement for extremely high pressures limits their practical applications. In this study, YH4 is adopted as a base material, with partial substitution of Yttrium (Y) by Scandium (Sc), Lanthanum (La), and Zirconium (Zr). Pure YH4, stable at 120 GPa, exhibits a critical temperature (Tc) of 84-95 K. Substituting half of the Y atoms increases Tc to 124.43 K for (Y,Sc)H4 at 100 GPa but reduces it to 101.24 K for (Y,La)H4 at 120 GPa. In contrast, (Y,Zr)H4 at 200 GPa shows a further suppressed Tc of 69.55 K. The remarkable superconductivity in (Y,Sc)H4 might be related to its unique phonon dispersion without optical-acoustic gap, compressed Y-H bonds, and significant electron delocalization under pressure, collectively boosting electron-phonon interactions. Furthermore, the lowest optical phonons play a crucial role in the superconductivity of these materials. This work suggests that substituting Y with same-group metal elements is an effective strategy to enhance Tc in hydride superconductors.

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Xuejie Li, Yuzhou Hao, Yujie Liu, Xiaoying Wang, Turab Lookman, Jun Sun, Xiangdong Ding, Zhibin Gao. 2025-09-22. Same-group element replacement enhances superconductivity in clathrate-like YH4. https://arxiv.org/abs/2509.17501

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