Preprint Article Version 1 This version is not peer-reviewed

Pressure-Induced Graphene-like Si Layer in Ductile RuSi2 with Ambient-Pressure Superconductivity and High Hardness

Version 1 : Received: 6 October 2024 / Approved: 7 October 2024 / Online: 7 October 2024 (13:40:00 CEST)

How to cite: Zhang, C.; Wang, Y.; Li, M.; Yang, F.; Gao, K.; Jin, Y.; Sun, W. Pressure-Induced Graphene-like Si Layer in Ductile RuSi2 with Ambient-Pressure Superconductivity and High Hardness. Preprints 2024, 2024100466. https://doi.org/10.20944/preprints202410.0466.v1 Zhang, C.; Wang, Y.; Li, M.; Yang, F.; Gao, K.; Jin, Y.; Sun, W. Pressure-Induced Graphene-like Si Layer in Ductile RuSi2 with Ambient-Pressure Superconductivity and High Hardness. Preprints 2024, 2024100466. https://doi.org/10.20944/preprints202410.0466.v1

Abstract

Of particular interest is the serendipity of distinctive nonmetallic layered frameworks with the stoichiometry of 1:2 in the binary metallic compounds within inorganic chemistry and materials science. This not only gives rise to the unexpected properties, especially the distinguished superconductivity, as reflected in MgB2, MoB2, NaC2, LaP2 and CeP2, but also strengthens the cognition of the elemental contributions. Although various investigations on the superconducting performances in the alkali, alkaline-earth and rare-earth metal disilicides containing the silicon layers have been reported, the pursuit of superconductors with silicon-planar framework in transition metal disilicides remain unknown up to now. In the present work, crystal structure searches and first-principles calculations were thoroughly conducted in RuSi2 within the pressure range of 0-300 GPa to uncover the novel structures, incredible silicon building block and the amazing properties. The ground orthorhombic Cmca-RuSi2 phase at ambient pressure is a semiconductor with the band gap of 0.485 eV, whose hardness can reach 31.7 GPa. Even more intriguingly, the high-pressure orthorhombic Cmcm-RuSi2 configuration with the fabulous graphene-like silicon-layer, which can be theoretically stabilized with the transformation pressure of 50.97 GPa, can be unexpectedly recovered to ambient pressure. Electron-phonon coupling calculations unravels that it possesses the metallic trait with an estimated Tc value of 1.43 K at 75 GPa, which increases to 10.07 K under ambient pressure. The enhanced Tc stems from the increased density of states at the Fermi level and associated with the coupled vibrations between Ru and the planar Si layer. Meanwhile, the hardness value for Cmcm-RuSi2 is 26.8 GPa under ambient pressure, which further results from the three-dimensional covalent Ru-Si and Si-Si building blocks. The coexistence of superconductivity and high hardness in the Cmcm-RuSi2 configuration under ambient pressure will pave the way for delving into more binary transition-metal silicides and correlated ternary silicides with the profound silicon layers.

Keywords

transition metal disilicide; 2D silicon layer; first principles; electronic property; superconductivity; hardness

Subject

Chemistry and Materials Science, Physical Chemistry

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