Ferromagnetic Ground State of Two-Band Hubbard Model with One Electron per Site

• Authors: J. Schulenburg , J. Richter
• Languages of publication: EN

Abstracts

EN

We study the multiband mechanism to favour a ferromagnetic insulating ground state within a two-band Hubbard model. Besides perturbation theory we use exact diagonalization studies to examine the ground state of chains and 2D-lattices. According to second order perturbation theory the exact diagonalization yields a fully polarized ferromagnetic ground state, if the hopping between two ground state orbitals of neighbouring atoms t_{gg} is small and the hopping between a ground state orbital and an excited orbital t_{ge} dominates. However, in contrast to the suggestion from the second order perturbation theory this ferromagnetic state is stable only for very small hopping integrals U≫ t_{ge}>t_{gg}. For larger t _{ge} quantum interference effects lead to complex magnetic structures.

Keywords

EN

75.40.Mg; 75.30.Et; 75.50.Dd; 75.10.Lp

• Publisher: Institute of Physics, Polish Academy of Sciences
• Journal: Acta Physica Polonica A
• Year: 1997
• Volume: 91
• Issue: 2
• Pages: 367-370

Dates

published

1997-02

Contributors

author

J. Schulenburg

• Institut für Theoretische Physik, Universität Magdeburg, P.O. Box 4120, 39016 Magdeburg, Germany

author

J. Richter

• Institut für Theoretische Physik, Universität Magdeburg, P.O. Box 4120, 39016 Magdeburg, Germany