Abstract
The interaction energy of the Hubbard model is regarded as a functional of the single-particle density matrix in the framework of lattice density-functional theory. The local character of the Hubbard interaction is exploited to express as a sum of local contributions , for which a simple semilocal scaling approximation is proposed. The method is applied to the ionic Hubbard model on one- and two-dimensional lattices with homogeneous and inhomogeneous Coulomb repulsions. Results are given for the kinetic and Coulomb energies, interatomic charge transfers, local magnetic moments, and charge gaps. Goals and limitations of the functional are discussed by comparison with exact results.
1 More- Received 21 January 2016
- Revised 13 June 2016
DOI:https://doi.org/10.1103/PhysRevB.94.045102
©2016 American Physical Society