Fig. 3: Superconducting dimensional crossover in Sm-based infinite layer nickelates and electronic structure measured by resonant inelastic X-ray scattering.
a, b Are normalized μ0Hc2/Tc(0 T) against reduced temperature T/Tc(0 T) of RE0.8Sr0.2NiO2 (RE: La, Pr, Nd and Sm) for \(H\perp c\) and H//c. The data for La-, Pr- and Nd-series are adapted from Ref. 15. The dashed lines indicate the Pauli limit of μ0Hc2 = 1.86 Tc(0 T). c Shows the upper critical field μ0Hc2,50% as a function of the polar rotation angle θ measured at 5 K. Here, the cyan line is a fit using the 2D Tinkham’s model, while the dashed line is a fit using the anisotropic 3D GL model. The red line is a fit using both 2D and 3D models with the ratio of the 3D component, β. Inset of (c) is a schematic of the measurement geometry. d–g Are Tc,50% as a function of θ measured at 9 T for the SSNO, SCSE0.06, SCSE0.12 and SCE0.2 thin films, respectively. The red lines are fits to both 2D and 3D models with the ratio of the 3D component, β’. h, i Are the resonant inelastic X-ray scattering (RIXS) energy loss maps as a function of incident energy for two light polarizations taken on a SCE0.2 sample. j Is the integrated intensity for both light polarizations.
