https://doi.org/10.1140/epjb/e2008-00462-8
Band effects on the conductivity for a two-band Hubbard model
1
Department of Physics and Institute of Theoretical Physics, The Chinese University of Hong Kong, Hong Kong, P.R. China
2
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, P.R. China
Corresponding author: a junpengcao@aphy.iphy.ac.cn
Received:
23
July
2008
Revised:
5
September
2008
Published online:
18
December
2008
The band effects on the conductivity of a one-dimensional two-band Hubbard model is studied based on the ground state energy analysis. It is found that the system with filling factor one is a metal at zero temperature if the on-site interaction U is smaller than a critical value Uc, and is an insulator if U is larger than Uc. The value of metal-insulator transition point Uc is obtained. This result is different from that of 1D single-band Hubbard model where the quantum phase transition point Uc=0. Therefore, the orbital degree of freedom plays an essential role in the states of matter.
PACS: 71.30.+h – Metal-insulator transitions and other electronic transitions / 71.10.Fd – Lattice fermion models (Hubbard model, etc.) / 74.70.-b – Superconducting materials
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2008
