Hydrogen is not necessary for superconductivity in topotactically reduced nickelates

• DOI: 10.48550/arxiv.2403.01796
• Publication Date: 2024-03-04
• Authors: Purnima P. Balakr...; Dan Ferenc Segedin; L. E. Chow; Patrick Quarterman; Shin Muramoto; Mythili Surendran; Ranjan Kumar Patel; Harrison LaBollita; Grace A. Pan; Qi Song; Yang Zhang; Ismail El Baggari; Koushik Jagadish; Yu‐Tsun Shao; Berit H. Goodge; Lena F. Kourkoutis; S. Middey; Antía S. Botana; Jayakanth Ravicha...; Ariando Ariando; Julia A. Mundy; Alexander J. Grutter

A key open question in the study of layered superconducting nickelate films is role that hydrogen incorporation into lattice plays appearance state. Due to challenges stabilizing highly crystalline square planar films, are prepared by deposition a more stable parent compound which then transformed target phase via topotactic reaction with strongly reducing agent such as CaH$_2$. Recent studies, both experimental and theoretical, have introduced possibility from may be critical for superconductivity. In this work, we use secondary ion mass spectrometry examine La$_{1-x}$X$_x$NiO$_2$ / SrTiO$_3$ (X = Ca Sr) Nd$_6$Ni$_5$O$_{12}$ NdGaO$_3$ along non-superconducting NdNiO$_2$ (Nd,Sr)NiO$_2$ SrTiO$_3$. We find no evidence extensive across broad range samples, including films. Theoretical calculations indicate broadly energetically unfavorable these systems, supporting our conclusion not generally required achieve state square-planar nickelates.