Superconductivity in pressurized trilayer La₄Ni₃O_10−δ single crystals

The pursuit of discovering new high-temperature superconductors that diverge from the copper-based model^1–3 has profound implications for explaining mechanisms behind superconductivity and may also enable new applications^4–8. Here our investigation shows that the application of pressure effectively suppresses the spin–charge order in trilayer nickelate La₄Ni₃O_10−δ single crystals, leading to the emergence of superconductivity with a maximum critical temperature (T_c) of around 30 K at 69.0 GPa. The d.c. susceptibility measurements confirm a substantial diamagnetic response below T_c, indicating the presence of bulk superconductivity with a volume fraction exceeding 80%. In the normal state, we observe a strange metal behaviour, characterized by a linear temperature-dependent resistance extending up to 300 K. Furthermore, the layer-dependent superconductivity observed hints at a unique interlayer coupling mechanism specific to nickelates, setting them apart from cuprates in this regard. Our findings provide crucial insights into the fundamental mechanisms underpinning superconductivity, while also introducing a new material platform to explore the intricate interplay between the spin–charge order, flat band structures, interlayer coupling, strange metal behaviour and high-temperature superconductivity.