Orbital compass model as an itinerant electron system
Department of Physics, Tohoku University - Sendai 980-8578, Japan
Accepted: 29 November 2011
The two-dimensional orbital compass model is studied as an interacting itinerant electron model. A Hubbard-type tight-binding model, from which the orbital compass model is derived in the strong-coupling limit, is identified. This model is analyzed by the random-phase approximation (RPA) and the self-consistent RPA methods from the weak coupling. Anisotropy for the orbital fluctuation in the momentum space is qualitatively changed by the on-site Coulomb interaction. This result is explained by the fact that the dominant fluctuation is changed from the intra-band nesting to the inter-band one by increasing the interaction.
PACS: 75.25.Dk – Orbital, charge, and other orders, including coupling of these orders / 75.10.Lp – Band and itinerant models / 75.47.Lx – Magnetic oxides
© EPLA, 2012