Stable Structures and Superconductivity in a Y-Si System under High Pressure

Recently, the discovery of superconductivity in compressed electrides offers a promising route toward searching for high superconductivity in a high-pressure community. However, only a few superconducting electrides have been successfully found thus far, thereby limiting the variety of superconducting electride examples. In this work, we performed extensive structure searches on a high-pressure Y-Si system by using CALYPSO structure prediction methodology. Our simulations identified several stable stoichiometries of YSi, YSi2, YSi3, Y5Si3, Y,Si, and Y3Si under high pressure. These structures contain a diversity of structure configurations, including silicon chains, Si-3 trilaterals, Si-4 quadrilaterals, Si-6 hexagons, Si-8 rings, a Si-4-Si-6-Si-8 frame, as well as a silicon layer. Remarkably, Y3Si is predicted to be an electride with a superconducting critical temperature (T-c) of similar to 11.2 and 14.5 K at 30 and SO GPa, respectively. These results highlight the role of the electrons at the Fermi surface in determining the superconductivity of predicted structures.

Automated summary

By conducting extensive structure searches on a high-pressure Y-Si system using the CALYPSO structure prediction methodology, multiple stable stoichiometries of YSi, YSi2, YSi3, Y5Si3, YSi, and Y3Si were identified. Among these structures, Y3Si was predicted to be an electride with superconducting critical temperatures of approximately 11.2 and 14.5 K at 30 and 50 GPa, respectively, showcasing the significant role of electrons at the Fermi surface in determining the superconductivity of the predicted structures.