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arXiv · 1206.2822

Site-selective Mott transition in rare earth nickelates

Hyowon Park·Andrew J. Millis·Chris A. Marianetti
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Abstract

A combination of density functional and dynamical mean field theory calculations are used to show that the remarkable metal-insulator transition in the rare earth nickelate perovskites arise from a site-selective Mott phase, in which the $d$-electrons on a half of the Ni ions are localized to form a fluctuating moment while the $d$-electrons on other Ni ions form a singlet with holes on the surrounding oxygen ions. The calculation reproduces key features observed in the nickelate materials, including an insulating gap in the paramagnetic state, a strong variation of static magnetic moments among Ni sites and an absence of "charge order". A connection between structure and insulating behavior is documented. The site-selective Mott transition may be a more broadly applicable concept in the description of correlated materials.

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Hyowon Park, Andrew J. Millis, Chris A. Marianetti. 2012-06-13. Site-selective Mott transition in rare earth nickelates. https://doi.org/10.1103/physrevlett.109.156402

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