Engineering correlation effects via artificially designed oxide superlattices.
Ab initio calculations are used to predict that a superlattice composed of layers of LaTiO3 and LaNiO3 alternating along the [001] direction is a S=1 Mott insulator with large magnetic moments on the Ni sites, negligible moments on the Ti sites and a charge transfer gap set by the energy difference between Ni d and Ti d states, distinct from conventional Mott insulators. Correlation effects are enhanced on the Ni sites via filling the oxygen p states and reducing the Ni-O-Ni bond angle. Small hole (electron) doping of the superlattice leads to a two-dimensional single-band situation with holes (electrons) residing on the Ni d(x2-y2) (Ti d(xy)) orbital and coupled to antiferromagnetically correlated spins in the NiO2 layer.
Department of Physics, Columbia University, New York, New York 10027, USA and Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, USA.
Hanghui
H
Chen
Andrew J
AJ
Millis
Chris A
CA
Marianetti