Unexpected Xe cations and superconductivity in Y-Xe compounds under pressure.

摘要: The metal-based noble gas compounds exhibit interesting behavior of electronic valence states under pressure. For example, Xe upon compression can gain electrons from the alkali metal, or lose unexpectedly to Fe and Ni, toward formation stable metal compounds. In addition, Na2He is not even stabilized by local chemical bonds but via long-range Coulomb interactions. Herein, using first-principles calculations unbiased structure searching techniques, we uncover that transition Y able react with above 60 GPa within various Y-Xe stochiometries, namely YXe, YXe2, YXe3 Y3Xe structures. Surprisingly, it found all resulting are intermetallic atoms positively charged. We also argue pressure-induced changes energy orbital filling responsible for electron transfer Y. Meanwhile, Peierls-like mechanism stabilize energetically most favorable YXe-Pbam phase. Furthermore, predicted YXe-Pbam, YXe-Pnnm, YXe3-I4/mcm phases discovered be phonon-mediated superconductors pressure, critical superconducting temperatures in range approximately 3-4K, 7-10K, 5-6K, respectively. summary, our work promotes further understanding crystal structures properties