paper

Quantum Confinement Induced Molecular Mott Insulating State in LaNiO

arXiv:1008.2707 · doi:10.1103/PhysRevLett.105.266402

Abstract

The recently synthesized layered nickelate LaNiO, with its cuprate-like NiO layers, seemingly requires a Ni1 ()+2Ni2 () charge order, together with strong correlation effects, to account for its insulating behavior. Using density functional methods including strong intra-atomic repulsion (Hubbard U), we obtain an insulating state via a new mechanism: {\it without charge order}, Mott insulating behavior arises based on quantum coupled, spin-aligned Ni2-Ni1-Ni2 states across the trilayer (rather than based on atomic states), with antiferromagnetic ordering within layers. The weak and frustrated magnetic coupling between cells may account for the small spin entropy that is removed at the Néel transition at 105 K and the lack of any diffraction peak at the Néel point.

4 pages, 3 figures

References in corpus (3)

Cited by in corpus (32)