High Pressure Synthesis & Superconductivity of Ytterbium Polyhydrides

Ytterbium polyhydrides were synthesized through in-situ high pressure laser heating techniques utilizing a diamond anvil cell. The temperature dependence of resistance measurement at high pressure demonstrates that the sample undergoes a superconducting transition at 11.5 K at 180 GPa. The investigation of SC under magnetic field indicates that the upper critical field at zero temperature μ₀H_c2(0) is ~5 Tesla. From the analysis of the in-situ high pressure X-ray diffraction experiments, the observed superconductivity is proposed to arise from the Pm3n Yb₄H₂₃ phase. It is speculated that the low superconducting transition temperature T_c in Yb₄H₂₃ might be associated with the unusual local magnetic moment in Yb at pressure.