Superconductivity in pressurized trilayer nickelate La4Ni3O10-δ single crystals

The search for new high-temperature superconductors beyond the copper-based paradigm offers exciting opportunities to deepen our understanding of superconductivity mechanisms and explore new applications. In this talk, I will present our successful synthesis of high-quality trilayer nickelate La₄Ni₃O_10-δ single crystals with minimal oxygen deficiency, achieved through the high-pressure optical floating zone technique. Our results show that applying pressure effectively suppresses spin and charge order in La₄Ni₃O_10-δ​, leading to the emergence of superconductivity with a maximum T_c​ of around 30 K at 69.0 GPa. Susceptibility measurements reveal a strong diamagnetic response below T_c​, confirming the presence of bulk superconductivity. In the normal state, we observe 'strange metal' behavior, marked by linear temperature-dependent resistance up to 300 K. This system's layer-dependent superconductivity suggests a distinct interlayer coupling mechanism, distinct from cuprates. These findings offer insights into the mechanisms of superconductivity and introduce a new material platform to study the interplay between the spin/charge order, flat band structure, interlayer coupling, strange metal behavior and superconductivity.