Non-Fermi-Liquid Behavior of Superconducting SnH\(_4\)

• Published in: arXiv.org 2023-03
• Main Authors: Troyan, Ivan A, Semenok, Dmitrii V, Ivanova, Anna G, Sadakov, Andrey V, Zhou, Di, Kvashnin, Alexander G, Kruglov, Ivan A, Sobolevskiy, Oleg A, Lyubutina, Marianna V, Perekalin, Dmitry S, Helm, Toni, Tozer, Stanley W, Bykov, Maxim, Goncharov, Alexander F, Pudalov, Vladimir M, Lyubutin, Igor S
• Format: Article
• Language: English
• Subjects: Anomalies; Critical current density; Cuprates; Fermi liquids; Magnetic fields; Magnetoresistance; Magnetoresistivity; Superconductivity; Superconductors; Temperature; Temperature dependence
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2303.06339

We studied chemical interaction of Sn with H\(_2\) by X-ray diffraction methods at pressures of 180-210 GPa. A previously unknown tetrahydride SnH\(_4\) with a cubic structure (\({fcc}\)) exhibiting superconducting properties below ${T}$$_C\( = 72 K was obtained; the formation of a high molecular \){C2/m}\(-SnH\)_{14}\( superhydride and several lower hydrides, \){fcc}\( SnH\)_2\( and \){C2}\(-Sn\)_{12}\(H\)_{18}\(, was also detected. The temperature dependence of critical current density \){J}$$_C\((T) in SnH\)_4\( yields the superconducting gap 2\)\Delta\((0) = 23 meV at 180 GPa. SnH\)_4\( has unusual behavior in strong magnetic fields: \){B,T}\(-linear dependences of magnetoresistance and the upper critical magnetic field \){B}$$_{C2}\((T) \)\propto\( (\){T}$$_C\( - \){T}\(). The latter contradicts the Wertheimer-Helfand-Hohenberg model developed for conventional superconductors. Along with this, the temperature dependence of electrical resistance of \){fcc}\( SnH\)_4$ in non-superconducting state exhibits a deviation from what is expected for phonon-mediated scattering described by the Bloch-Gr\"uneisen model, and is beyond the framework of the Fermi liquid theory. Such anomalies occur for many superhydrides, making them much closer to cuprates than previously believed.