This title appears in the Scientific Report :
2006
Please use the identifier:
http://dx.doi.org/10.1140/epjb/e2006-00248-0 in citations.
Non-Fermi-liquid phases in the two-band Hubbard model: Finite-temperature exact diagonalization study of Hund's rule coupling
Non-Fermi-liquid phases in the two-band Hubbard model: Finite-temperature exact diagonalization study of Hund's rule coupling
The two-band Hubbard model involving subbands of different widths is investigated via finite-temperature exact diagonalization (ED) and dynamical mean field theory (DMFT). In contrast to the quantum Monte Carlo (QMC) method which at low temperatures includes only Ising-like exchange interactions to...
Saved in:
Personal Name(s): | Liebsch, A. |
---|---|
Costi, T. A. | |
Contributing Institute: |
Theorie III; IFF-TH-III JARA-HPC Theorie I; IFF-TH-I |
Published in: | The @European physical journal / B, 51 (2006) S. 523 |
Imprint: |
Berlin
Springer
2006
|
Physical Description: |
523 |
DOI: |
10.1140/epjb/e2006-00248-0 |
Document Type: |
Journal Article |
Research Program: |
Non-equilibrium dynamics of fermionic atoms in optical lattices; transport at oxide interfaces Kondensierte Materie |
Series Title: |
European Physical Journal B
51 |
Subject (ZB): | |
Publikationsportal JuSER |
The two-band Hubbard model involving subbands of different widths is investigated via finite-temperature exact diagonalization (ED) and dynamical mean field theory (DMFT). In contrast to the quantum Monte Carlo (QMC) method which at low temperatures includes only Ising-like exchange interactions to avoid sign problems, ED permits a treatment of Hund's exchange and other onsite Coulomb interactions on the same footing. The role of finite-size effects caused by the limited number of bath levels in this scheme is studied by analyzing the low-frequency behavior of the subband self-energies as a function of temperature, and by comparing with numerical renormalization group (NRG) results for a simplified effective model. For half-filled, non-hybridizing bands, the metallic and insulating phases are separated by an intermediate mixed phase with an insulating narrow and a bad-metallic wide subband. The wide band in this phase exhibits different degrees of non-Fermi-liquid behavior, depending on the treatment of exchange interactions. Whereas for complete Hund's coupling, infinite lifetime is found at the Fermi level, in the absence of spin-flip and pair-exchange, this lifetime becomes finite. Excellent agreement is obtained both with new NRG and previous QMC/DMFT calculations. These results suggest that-finite temperature ED/DMFT might be a useful scheme for realistic multi-band materials. |