On the Half-Filled-Band Hubbard Model

Dario Cabib, T. A. Kaplan, Hugh C. Wolfe +2 more

David Djajaputra, J. Ruvalds

Hiromi Otsuka

Using the quantum Monte Carlo simulation technique for the lattice fermion systems, we study the charge susceptibility of the two-dimensional Hubbard near the half-filled band. Lattice sizes up to 6×6 and inverse temperatures up to 6 t ( t : hopping parameter) are studied. We find that the behavior of the charge susceptibility is strongly dependent on the electron concentration at low temperature: the charge susceptibility is suppressed at the half-filled band, while it is considerably enhanced in non-half-filled band cases by the electron correlation. The above behavior of the charge susceptibility is quite similar to the recent Bethe-Ansatz result for the one-dimensional Hubbard model.

B. Mehlig, Peter Fulde

Feng Chen, He-Ping Ying, Tiefeng Xu +1 more

The electrical conductivity of the one-band Hubbard model on a two-dimensional square lattice at half-filling is studied through the grand canonical quantum Monte Carlo method. Our results support that there exists an insulator-to-metal transition for the half-filled Hubbard model at high temperature.

Wenzhu Li, Feng Chen, Tiefeng Xu +1 more

The finite-temperature optical conductivity of the two-dimensional Hubbard model is studied by means of the grand canonical quantum Monte Carlo method. Results are reported for the half-filled and nonhalf-filled band. The formation and variation of Hubbard gap are observed. For the half-filled band case, our results support that there exists a high-temperature insulator-metal transition.