TY - JOUR
T1 - Resolving the polar interface of infinite-layer nickelate thin films
AU - Goodge, Berit H.
AU - Geisler, Benjamin
AU - Lee, Kyuho
AU - Osada, Motoki
AU - Wang, Bai Yang
AU - Li, Danfeng
AU - Hwang, Harold Y.
AU - Pentcheva, Rossitza
AU - Kourkoutis, Lena F.
PY - 2023/4
Y1 - 2023/4
N2 - Nickel-based superconductors provide a long-awaited experimental platform to explore possible cuprate-like superconductivity. Despite similar crystal structure and d electron filling, however, superconductivity in nickelates has thus far only been stabilized in thin-film geometry, raising questions about the polar interface between substrate and thin film. Here we conduct a detailed experimental and theoretical study of the prototypical interface between Nd1−xSrxNiO2 and SrTiO3. Atomic-resolution electron energy loss spectroscopy in the scanning transmission electron microscope reveals the formation of a single intermediate Nd(Ti,Ni)O3 layer. Density functional theory calculations with a Hubbard U term show how the observed structure alleviates the polar discontinuity. We explore the effects of oxygen occupancy, hole doping and cation structure to disentangle the contributions of each for reducing interface charge density. Resolving the non-trivial interface structure will be instructive for future synthesis of nickelate films on other substrates and in vertical heterostructures. © 2023, The Author(s), under exclusive licence to Springer Nature Limited.
AB - Nickel-based superconductors provide a long-awaited experimental platform to explore possible cuprate-like superconductivity. Despite similar crystal structure and d electron filling, however, superconductivity in nickelates has thus far only been stabilized in thin-film geometry, raising questions about the polar interface between substrate and thin film. Here we conduct a detailed experimental and theoretical study of the prototypical interface between Nd1−xSrxNiO2 and SrTiO3. Atomic-resolution electron energy loss spectroscopy in the scanning transmission electron microscope reveals the formation of a single intermediate Nd(Ti,Ni)O3 layer. Density functional theory calculations with a Hubbard U term show how the observed structure alleviates the polar discontinuity. We explore the effects of oxygen occupancy, hole doping and cation structure to disentangle the contributions of each for reducing interface charge density. Resolving the non-trivial interface structure will be instructive for future synthesis of nickelate films on other substrates and in vertical heterostructures. © 2023, The Author(s), under exclusive licence to Springer Nature Limited.
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U2 - 10.1038/s41563-023-01510-7
DO - 10.1038/s41563-023-01510-7
M3 - RGC 21 - Publication in refereed journal
SN - 1476-1122
VL - 22
SP - 466
EP - 473
JO - Nature Materials
JF - Nature Materials
IS - 4
ER -