Magnetic transitions in strong coupling expansions for nearly degenerate states
Strongly Correlated Electrons
2012-08-30 v2
Abstract
We consider a strong coupling expansion for a two-band Hubbard model on two sites with nearly degenerate states. A comparative analysis is performed for different schemes of perturbation theory which are applicable to systems with nearly degenerate states. A fourth order approach which builds on a four-dimensional low-energy subspace with nearly degenerate states captures accurately the transition from an antiferromagnetic to a ferromagnetic ground state at large on-site Coulomb interaction.
Keywords
Cite
@article{arxiv.1205.0425,
title = {Magnetic transitions in strong coupling expansions for nearly degenerate states},
author = {Raymond Fresard and Christian Hackenberger and Thilo Kopp},
journal= {arXiv preprint arXiv:1205.0425},
year = {2012}
}
Comments
15 pages, 6 figures; version corrects typos and other minor mistakes