title: Site-selective Mott transition in rare-earth-element nickelates.
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-element nickelate perovskites arises from a site-selective Mott phase, in which the d electrons on 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.
authors.affiliation: Department of Physics, Columbia University, New York, New York 10027, USA.
authors.forename: Hyowon
authors.initials: H
authors.lastname: Park
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Millis
authors.forename: Chris A
authors.initials: CA
authors.lastname: Marianetti