Origin of metal-insulator transition in rare-earth Nickelates

Swagata Acharya; Brooks Tellekamp; Jerome Jackson; Dimitar Pashov; Jeffrey L. Blackburn; Kirstin Alberi; Mark van Schilfgaarde

arXiv · 2511.14960

Origin of metal-insulator transition in rare-earth Nickelates

Swagata Acharya·Brooks Tellekamp·Jerome Jackson·Dimitar Pashov·Jeffrey L. Blackburn·Kirstin Alberi·Mark van Schilfgaarde

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Abstract

Rare-earth nickelates RNiO3 (R=rare-earth element) exhibit three kinds of phase transitions with decreasing temperature: a structural transition from a pseudo-cubic to a monoclinic phase, a metal- insulator transition (MIT), and a magnetic transition from a paramagnetic state to an ordered one. The first two occur at the same temperature, which has led to a consensus that the MIT is driven by lattice distortions. We show here that the primary driving force for the MIT is magnetic; however because of the unusual d7 configuration of Ni, additional flexibility in spin configurations are also needed which symmetry-lowing structural deformations make possible. The latter enable Ni to disproportionate into two kinds: a high-spin and a low-spin configuration, which allow the system to reduce its unfavorable orbital moment and also open a gap.

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Swagata Acharya, Brooks Tellekamp, Jerome Jackson, Dimitar Pashov, Jeffrey L. Blackburn, Kirstin Alberi, Mark van Schilfgaarde. 2025-11-18. Origin of metal-insulator transition in rare-earth Nickelates. https://arxiv.org/abs/2511.14960

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