Designing new metastable nickelate thin films isostructural to the cuprates

Despite over thirty years of intense experimental and theoretical effort, there remain outstanding questions on the origin of superconductivity in the cuprates. One strategy for gaining insight into this phase has been to probe materials which are isoelectronic to the cuprates and contain many of the same characteristics of the known high-TC superconductors. Recent work on bulk crystals of layered square planar nickelates, R₄Ni₃O₈ (R = La, Pr) has re-ignited interest in nickelates for this purpose [1]. Here, we use atomically-precise synthesis to construct a full series of R_n+1Ni_nO_3n+1 (n = 1 – 5) thin films which we then reduce to form R_n+1Ni_nO_2n+2. We aim to develop a systematic understanding of these different nickelate thin films and to correlate the electronic behavior with the local crystal structure and nickel valence state.

[1] Junjie Zhang, A. S. Botana, J. W. Freeland2 , D. Phelan , Hong Zheng , V. Pardo, M. R. Norman and J. F. Mitchell, “Large orbital polarization in a metallic square-planar nickelate,” Nature Phys 13, 864-870 (2017)