Intrinsic properties of bilayer nickelate thin films grown on LaAlO₃

Ambient-pressure superconductivity has recently been stabilized in compressively strained bilayer nickelate thin films grown on SrLaAlO₄ substrates, which impose a nominal in-plane compressive strain of -2.0%. This discovery provides an accessible platform to probe superconductivity in the novel d^7.5 electronic configuration. Despite tremendous progress achieved in this field, many open questions remain, particularly regarding how superconductivity and charge/spin orders evolve with epitaxial strain, and to what extent epitaxial strain can be considered analogous to hydrostatic pressure. Here, we report our recent efforts on the growth optimization, structural characterization, and transport properties of bilayer nickelate thin films on LaAlO₃ substrates, which impose a nominal compressive strain of -1.2%. We believe that understanding the intrinsic properties of bilayer nickelate thin films on LaAlO₃ is crucial, as it provides an important bridge between the superconducting films on SrLaAlO₄ and non-superconducting bulk counterparts.