Quasi-Hole Properties in Two-Dimensional Strongly Correlated Systems

Hideo Aoki, Kazuhiko Kuroki, 青木 秀夫 +1 more

Ian P. Mc Culloch, M. Gulácsi

The physical properties of two-dimensional interacting electron systems are of great current interest. An open question in the physics of low-dimensional fermionic models is whether their properties are described by standard Fermi-liquid theory or whether instead they show unconventional behaviour in strongly correlated electron systems. As the two-dimensional Hubbard model is the typical example of a strongly correlated electron system, we solve for this model the two-body problem in the vicinity of a half-filled Fermi sea. The results obtained show that for a low hole concentration the well known Fermi-liquid picture fails.

Rishabh Jha

H. Q. Lin

Using all appropriate symmetries for a two-dimensional square system, we have been able to diagonalize exactly the Hubbard Hamiltonian on the 4\ifmmode\times\else\texttimes\fi{}4 and 18-site lattices. We calculate the ground-state energies, hole-hole interactions, and various correlation functions as functions of the Coulomb repulsion U and band filling, and compare the Hubbard-model results with those obtained from the t-J and strong-coupling models.

Antonis D Mistriotis, H. Büttner, W. Pesch

The ground-state properties of several finite two-dimensional clusters were numerically investigated within the Hubbard model. In particular the spatial distribution of holes (with respect to the half-filled band case) is studied in detail. It is found that in systems with frustrated sites the holes prefer to occupy these sites for large U, and repel each other. This effect can be used to stabilise the antiferromagnetic order in the clusters by introducing coupling to additional sites.

Indrani Bose, Saurabh Gayen