Charge transfer and competing symmetry breaking drive orbital reconstruction and emergent ferromagnetism in insulating oxide superlattices
Year: 2026
Type: preprint
Abstract: Electron correlation, hopping, and ligand-to-metal charge transfer collectively lead to diverse electronic and magnetic phenomena in 3$d$ transition-metal oxides, where directional d orbitals make hopping highly sensitive to symmetry-dependent orbital overlap. Heterostructure engineering with atomically flat interfaces adds symmetry-breaking charge transfer as a further route to emergent behavior, yet whether interfacial mismatch between constituent oxides of a superlattice shapes ground states independent of epitaxial strain remains unresolved. Here we examine superlattices combining NdNiO$_3$ with Mott-insulating NdMnO$_3$. Varying layer thickness and combining transport with X-ray spectroscopy, we show that electron transfer from NdMnO$_3$ to NdNiO$_3$ drives a room-temperature insulating state with a distinct electronic structure, accompanied by a reversal in orbital symmetry beyond simple strain considerations, underscoring the interface's central role. These reconstructions stabilize an emergent ferromagnetic insulating state arising from interfacial Ni$^{2+}$-O-Mn$^{4+}$ superexchange. Our results establish a pathway to interface-engineered ferromagnetic insulating phases via competing interactions, with potential for spin-insulatronic applications.
Source: arXiv (Cornell University)
Authors: Bhattacharya, Nandana, Patel, Ranjan Kumar, Kumar, Siddharth, Chowdhury, Sourav, Beniwal, Manav, Joshi, Suresh Chandra, Mandal, Prithwijit, Dey, Jayjit Kumar, Li, Weibin, Valvidares, Manuel, Zhang, Zhan, Zhou, Hua, Gloskovskii, Andrei, Schlueter, Christoph, Klewe, Christoph, Middey, Srimanta
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
Funders: U.S. Department of Energy, Arthritis National Research Foundation, Indian Institute of Science, Department of Science and Technology, Ministry of Science and Technology, India, Bundesministerium für Bildung und Forschung, Ministry of Education, India, Office of Science, Deutsches Elektronen-Synchrotron, Mission on Nano Science and Technology, Argonne National Laboratory
OpenAlex ID: W7204804945