LaNiO
3 thin films with different thicknesses were grown on high-quality STO (111) and LAO (111) substrates (Crystec, Germany) by pulsed laser interval deposition27 38 40 (laser frequency: 18 Hz). In order to avoid additional surface defects on substrate, formed by the chemical treatment for achieving single termination48 , as received substrates were used. 50 mTorr partial pressure of oxygen was maintained during the growth and all of the grown samples were subsequently post annealed in-situ for 30 min in 1 atm of ultra pure oxygen at growth temperature (670°C), which was found to be essential to maintain correct oxygen stoichiometry for the (001) oriented LNO/LAO heterostructures27 . The films were characterized ex-situ by laboratory-based XRD (
Panalytical Xpert Pro MRD [Panalytical, Almelo]). Ni
L3,2 edge and O
K edge XAS spectra were taken at room temperature at the 4-ID-C beam line of the Advanced Photon Source at Argonne National Laboratory. Electrical d.c. transport characterization was performed on a commercial physical properties measurement system (PPMS) with van der Paw geometry.
Middey S., Rivero P., Meyers D., Kareev M., Liu X., Cao Y., Freeland J.W., Barraza-Lopez S, & Chakhalian J. (2014). Polarity compensation in ultra-thin films of complex oxides: The case of a perovskite nickelate. Scientific Reports, 4, 6819.
