Scientists of the Fudan University in Shanghai present groundbreaking research on the emergence of superconductivity in trilayer nickelate crystals under high pressure. The nickelate single crystals were grown at an oxygen pressure of 18-22 bar using a ScIDre HKZ floating zone furnace.
The authors demonstrate that applying pressure to these crystals suppresses spin and charge order, leading to superconductivity with a maximum critical temperature T_c of around 30 K at 69.0 GPa. Notably, the d. c. susceptibility measurements reveal a significant diamagnetic response below T_c, indicating bulk superconductivity with a volume fraction exceeding 80%. Additionally, the study observes strange metal behavior in the normal state, characterized by linear temperature-dependent resistance up to 300 K. The unique interlayer coupling mechanism specific to nickelates, as opposed to cuprates, is highlighted as a key factor in the observed layer-dependent superconductivity.
These findings provides valuable insights into the fundamental mechanisms of superconductivity and introduce a new material platform for exploring interactions between spin/charge order, flat band structures, interlayer coupling, strange metal behavior, and high-temperature superconductivity.