Abstract
Electronic structure of stripe ordered is investigated. The system with is insulator, in calculations, and shows charge and spin stripe, consistent with the experimental results. A highly correlated system of is studied by using exact diagonalization of the multiorbital many-body Hamiltonian derived from LDA calculations and including on-site and intersite Coulomb interactions. The fluctuation of the residual spin on (hole) site couples with the charge fluctuation between and states and this correlation lowers the total energy. The resultant ground state is an insulator with charge and spin stripe of the energy gap , consistent with the observed one. The on-site Coulomb interaction stabilizes integral valency of each Ni ion ( and ), but does not induce the charge order. Two quantities, intersite Coulomb interaction and anisotropy of hopping integrals, play an important role to form the charge and spin stripe order in a system of .
3 More- Received 15 August 2007
DOI:https://doi.org/10.1103/PhysRevB.76.165114
©2007 American Physical Society