Thursday, October 22, 2026
4:00 pm-5:00 pm
Competing Spin Density Wave and Superconducting Order in Bilayer Nickelate La3Ni2O7 thin films
Understanding the interplay between magnetism and superconductivity remains a central challenge in unconventional superconductors. In this talk, I will discuss our recent work on epitaxial La₃Ni₂O₇ thin films, where we first realize a superconducting transition near 30 K in films grown on LaAlO₃(100). By controlling oxygen stoichiometry at fixed epitaxial strain and combining resonant elastic and inelastic X-ray scattering with angle-resolved photoemission spectroscopy, we compare superconducting and non-superconducting films. We find a systematic evolution of spin-density-wave (SDW) correlations, from a sharp transition in non-superconducting samples to a weakened, crossover-like response in superconducting samples. The SDW wave vector remains near (1/4,1/4)(1/4,1/4) but shows a systematic incommensurate shift. Most importantly, the static SDW intensity decreases below Tc, while dynamic spin excitations exhibit reduced spectral weight and enhanced damping. These results reveal a direct interplay between magnetic order, spin dynamics, and superconductivity in bilayer nickelates.
