We investigate the magnetic instabilities of the nondegenerate (s-band) and a degenerate (d-
band) Hubbard model in two dimensions using many-body effects due to particle-particle …

The Hubbard model plays a special role in condensed matter theory as it is considered to be
the simplest Hamiltonian model one can write in order to describe anomalous physical …

Multiorbital Hubbard model Hamiltonians for the undoped parent compounds of the Fe-
pnictide superconductors are investigated here using mean-field techniques. For a realistic …

We study the zero temperature antiferromagnetic metal to antiferromagnetic insulator
transition using dynamical mean field theory and exact diagonalization methods. We find …

Phase diagrams of the two-dimensional one-band t− t′ Hubbard model are obtained within
the two-patch and temperature-cutoff many-patch renormalization group approaches. At …

To clarify the effects of next-nearest-neighbor electron hop** t′ on the spin, charge, and
pairing correlations, we studied the two-dimensional t− t′− U Hubbard model using the …

The perfect‐nesting instability towards antiferromagnetism of the Hubbard model is
suppressed by next‐nearest neighbor hop** t′. The asymptotic behavior of the critical …

The two-dimensional Hubbard model exhibits superconductivity with d-wave symmetry even
at<? format?> half-filling in the presence of a next-nearest neighbor hop**. Using …

The ground state for the half-filled t− t′ Hubbard model is treated within the Hartree-Fock
approximation and the slave-boson approach including correlations. The criterium for the …

In a half-filled Hubbard model on a square lattice, the next-nearest-neighbor hop**
causes spin frustration, and the collinear antiferromagnetic (CAF) state appears as the …