Nature of the low energy excitations in infinite-layer nickelates

The discovery of superconductivity in infinite-layer nickelate thin films has sparkled a flurry of theoretical and experimental studies mainly focusing on the properties that mirror that one’s of cuprates. Indeed, the electronic properties of the NiO2 plane are believed to be equivalent to the CuO2 planes. Resonant inelastic x-ray scattering (RIXS) measurements evidenced the presence of magnetic excitations with a bandwidth of circa 200 meV in SrTiO3-capped films. We could reproduce such a result on our capped samples but, on the other side, we did not find a clear evidence of such spin excitations for our un-capped ones. Here, we would like to needle down this dichotomy by performing RIXS measurements at the Ni L3-edge by using the polarimeter of the ERIXS spectrometer, to get useful insights on the possible magnetic properties of the low energy feature. Definitely, our results will shed light on the role played by the SrTiO3 capping layer on the appearing of the spin excitations.