Band effects on the conductivity for a two-band Hubbard model

path integral methods for single band hubbard model

we review various ways to express the partition function of the single-band hubard model as a path integral. the emphasis is made on the derivation of the action in the integrand of the path integral and the results obtained from this approach are discussed only briefly.   since the single-band hubbard model is a pure fermionic model on the lattice and its hamiltonian is a polynomial in creatio...

Novel Mott transitions in a nonisotropic two-band Hubbard model.

The Mott transition in a two-band Hubbard model involving subbands of different widths is studied as a function of temperature using dynamical mean field theory combined with exact diagonalization. The phase diagram is shown to exhibit two successive first-order transitions if the full Hund's rule coupling is included. In the absence of spin-flip and pair-exchange terms the lower transition rem...

Quantum phase transition in the two-band hubbard model.

The interaction between itinerant and Mott localized electronic states in strongly correlated materials is studied within dynamical mean field theory in combination with the numerical renormalization group method. A novel nonmagnetic zero temperature quantum phase transition is found in the bad-metallic orbital-selective Mott phase of the two-band Hubbard model, for values of the Hund's exchang...

Variational Monte Carlo study of the two-band Hubbard model

Suppression of Mott–Hubbard states and metal–insulator transitions in the two-band Hubbard model

I investigate band and Mott insulating states in a two-band Hubbard model, with the aim of understanding the differences between the idealised oneorbital model and the more realistic multi-band case. Using a projection ansatz I show that additional orbitals suppress the metal-insulator transition, leading to a critical coupling of approximately eight times the bare band-width. I also demonstrat...