A novel stable hydrogen-rich SnH8 under high pressure
Abstract
A first-principles calculation is applied to perform a comprehensive study of the Sn–H system. Besides the common tetravalent hydride, a novel SnH8 crystal with the space group Im2 is reported with the most dominant enthalpy from structure searching techniques. All the H atoms of SnH8 are in the form of H2 or H3 units with electrons localized around them, showing covalent bond character. The rich and multiple Fermi surface distribution displays a metallic feature. Further electron–phonon coupling calculations reveal the high Tc of 63–72 K at 250 GPa.