2012/06/13 by Hyowon Park, Andrew J. Millis, Chris A. Marianetti
Physics and Astronomy · #cond-mat.str-el #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevlett.109.156402
published as Phys. Rev. Lett. 109, 156402 (2012) · 4+ pages, 4 figures
arxiv created 2012/06/13 · arxiv updated 2013/08/29
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.