Topochemical Oxidation of Ruddlesden–Popper Nickelates Reveals Distinct Structural Family: Oxygen-Intercalated Layered Perovskites

Journal Article · Thu Jan 01 00:00:00 EST 2026 · Journal of the American Chemical Society

DOI:https://doi.org/10.1021/jacs.5c12712· OSTI ID:3025145

Segedin, Dan Ferenc; Kim, Jinkwon; LaBollita, Harrison; Taylor, Nicole K; Baek, Kyeong-Yoon; Sung, Suk Hyun; Turkiewicz, Ari B; Pan, Grace A; Jiang, Abigail Y; Bambrick-Santoyo, Maria; Schwaigert, Tobias; Kim, Casey K; Tenneti, Anirudh; Grutter, Alexander J; Muramoto, Shin; N’Diaye, Alpha T; Baggari, Ismail El; Walko, Donald A; Brooks, Charles M; Botana, Antia S ; Schlom, Darrell G; Zhou, Hua; Mundy, Julia A

Layered perovskitesincluding the Dion–Jacobson, Ruddlesden–Popper, and Aurivillius familiesexhibit a wide range of correlated electron phenomena, from high-temperature superconductivity to multiferroicity. Here, we report a new family of layered perovskites realized through topochemical oxidation of La n+1Ni n O3n+1+δ (n = 1–4) Ruddlesden–Popper nickelate thin films. Postgrowth ozone annealing induces a substantial c-axis expansion17.8% for La2NiO4+δ (n = 1)that monotonically decreases with increasing n. Surface synchrotron X-ray diffraction and coherent Bragg rod analysis (COBRA) reveal that this structural expansion arises from the intercalation of approximately δ ≈ 0.7–1.0 oxygen atoms into interstitial sites within the rock salt spacer layers, far exceeding the previous record of δ ≈ 0.3 for any Ruddlesden–Popper oxide. These oxygen-intercalated phases form a new class of layered perovskites with a spacer layer composition intermediate between the Ruddlesden–Popper and Aurivillius phases. Furthermore, oxygen intercalation induces metallicity, enhances nickel–oxygen hybridization, and suppresses oxygen octahedral rotations, a feature associated with high-temperature superconductivity in Ruddlesden–Popper nickelates. Our work establishes topochemical oxidation as a powerful approach to accessing highly oxidized, metastable phases across a broad range of layered oxide systems, offering new platforms to engineer electronic properties via intercalation chemistry.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: US Department of Energy; USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22), Scientific User Facilities Division (SC-22.3 )
• Grant/Contract Number: AC02-05CH11231
• OSTI ID: 3025145
• Journal Information: Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 6 Vol. 148
• Country of Publication: United States
• Language: English