Possible superconductivity at ∼70 K in tin hydride SnHx under high pressure

• Published in: Materials today physics 2022-01, Vol.22, p.100596, Article 100596
• Main Authors: Hong, F., Shan, P.F., Yang, L.X., Yue, B.B., Yang, P.T., Liu, Z.Y., Sun, J.P., Dai, J.H., Yu, H., Yin, Y.Y., Yu, X.H., Cheng, J.G., Zhao, Z.X.
• Format: Article
• Language: English
• Subjects: High pressure; Superconductivity; Tin hydrides
• ISSN: 2542-5293; 2542-5293
• DOI: 10.1016/j.mtphys.2021.100596

Hydrides of air non-sensitive IVA-group elements were predicted to be possible high temperature superconductors (HTS) by N.W. Ashcroft (PRL 92, 187002 (2004)), which inspired the exploration of hydrogen dominated metallic alloy-based HTS. Although the IVA-group hydrides have been investigated theoretically by several groups, the experimental realization of any superconducting IVA-group hydrides is still lacking. Here, we report on the observation of the possible superconducting transition at ∼70 K in a SnHx sample synthesized by laser heating Sn and ammonia borane inside a diamond anvil cell at ∼200 GPa. The main phase of the obtained sample can be indexed with the monoclinic C2/m SnH12 via comparison with the theoretical structural modes, which have distinct H-network with respect to the clathrate-type structure. A sudden drop of resistance and the systematic downward shift under external magnetic fields signal the occurrence of superconductivity in SnHx with an upper critical field μ0Hc2(0) ≈ 11.2 T, and the resistive broadening behavior in magnetic fields follows the trend of traditional standard superconductors. This work provides an alternative way to obtain metal hydrides HTS via p electron-metals rather than the active s or f electron-metals (such as Mg, Ca, La, Y, Ce), which will stimulate the experimental exploration of hydrides HTS in different element groups. A new metal hydride SnHx superconductor with Tc ≈ 72 K is synthesized at ∼200 GPa. [Display omitted] •A new hydride SnHx is synthesized at ∼200 GPa, and is confirmed to be a high-temperature superconductor (HTS) with Tc ≈ 72 K.•The obtained SnHx is a p-electron metal hydride superconductor containing H2 and H4 molecule-like units.•SnHx is the first experimentally synthesized HTS among the IVA-group hydrides.