Prediction of fully metallic {\sigma}-bonded boron framework induced high superconductivity above 100 K in thermodynamically stable Sr2B5 at 40 GPa

Xin Yang; Wenbo Zhao; Liang Ma; Wencheng Lu; Xin Zhong; Yu Xie; Hanyu Liu; Yanming Ma

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arXiv · 2310.13945

Prediction of fully metallic {\sigma}-bonded boron framework induced high superconductivity above 100 K in thermodynamically stable Sr2B5 at 40 GPa

Xin Yang·Wenbo Zhao·Liang Ma·Wencheng Lu·Xin Zhong·Yu Xie·Hanyu Liu·Yanming Ma

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Abstract

Metal borides have been considered as potential high-temperature superconductors since the discovery of record-holding 39 K superconductivity in bulk MgB2. In this work, we identified a superconducting yet thermodynamically stable F43m Sr2B5 at 40 GPa with a unique covalent sp3-hybridized boron framework through extensive first-principles structure searches. Remarkably, solving the anisotropic Migdal-Eliashberg equations resulted in a high superconducting critical temperature (Tc) around 100 K, exceeding the boiling point (77 K) of liquid nitrogen. Our in-depth analysis revealed that the high-temperature superconductivity mainly originates from the strong coupling between the metalized {\sigma}-bonded electronic bands and E phonon modes of boron atoms. Moreover, anharmonic phonon simulations suggest that F43m Sr2B5 might be recovered to ambient pressure. Our current findings provide a prototype structure with a full {\sigma}-bonded boron framework for the design of high-Tc superconducting borides that may expand to a broader variety of lightweight compounds.

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Xin Yang, Wenbo Zhao, Liang Ma, Wencheng Lu, Xin Zhong, Yu Xie, Hanyu Liu, Yanming Ma. 2023-10-21. Prediction of fully metallic {\sigma}-bonded boron framework induced high superconductivity above 100 K in thermodynamically stable Sr2B5 at 40 GPa. https://arxiv.org/abs/2310.13945

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