Thursday, June 14, 2012

1206.2822 (Hyowon Park et al.)

Site-selective Mott transition in rare earth nickelates    [PDF]

Hyowon Park, Andrew J. Millis, Chris A. Marianetti
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.
View original: http://arxiv.org/abs/1206.2822

No comments:

Post a Comment