Probing electronic and spin excitations in superconducting La3Ni2O7/SrLaAlO4 thin films

Recently, ambient-pressure superconductivity (SC) with Tc>40 K has been realized in La3Ni2O7 (LNO) thin films grown on SrLaAlO4 (SLAO) substrates that applies in-plane compressive epitaxial strain on LNO, making possible spectroscopic studies on LNO in the superconducting state employing soft X-rays. Our previous RIXS experiments on LNO/LAO, LNO/LSAT and LNO/STO performed at ID32, ESRF revealed that the spectral weight and energy of spin excitations are enhanced by the in-plane compressive strain, and their electronic structure could be effectively tuned by epitaxial strain, suggesting that spin fluctuations likely play a crucial role in mediating electron pairing in the superconducting phase of LNO. However, the spin dynamics and the detailed orbital energy landscape in LNO/SLAO remain to be explored experimentally. We aim to utilize RIXS to probe the spin and orbital excitations of LNO/SLAO thin films, with the goal of gaining deeper insights into the mechanisms underlying SC in LNO.