Kavli Affiliate: Darrell G. Schlom
| First 5 Authors: Dan Ferenc Segedin, Jinkwon Kim, Harrison LaBollita, Nicole K. Taylor, Kyeong-Yoon Baek
| Summary:
Layered perovskites such as the Dion-Jacobson, Ruddlesden-Popper, and
Aurivillius families host a wide range of correlated electron phenomena, from
high-temperature superconductivity to multiferroicity. Here we report a new
family of layered perovskites, realized through topotactic oxygen intercalation
of La_{n+1}Ni_{n}O_{3n+1} (n=1-4) Ruddlesden-Popper nickelate thin films grown
by ozone-assisted molecular-beam epitaxy. Post-growth ozone annealing induces a
large c-axis expansion – 17.8% for La_{2}NiO_{4} (n=1) – that monotonically
decreases with increasing n. Surface X-ray diffraction coupled with Coherent
Bragg Rod Analysis reveals that this structural expansion arises from the
intercalation of approximately 0.7 oxygen atoms per formula unit into
interstitial sites within the rock salt spacer layers. The resulting structures
exhibit a spacer layer composition intermediate between that of the
Ruddlesden-Popper and Aurivillius phases, defining a new class of layered
perovskites. Oxygen-intercalated nickelates exhibit metallicity and
significantly enhanced nickel-oxygen hybridization, a feature linked to
high-temperature superconductivity. Our work establishes topotactic oxidation
as a powerful synthetic approach to accessing highly oxidized, metastable
phases across a broad range of layered oxide systems, offering new platforms to
tune properties via spacer-layer chemistry.
| Search Query: ArXiv Query: search_query=au:”Darrell G. Schlom”&id_list=&start=0&max_results=3