https://doi.org/10.1007/PL00011085
Plaquette ground state in the two-dimensional SU(4) spin-orbital model
1
Laboratoire de Physique Quantique,
Université Paul Sabatier, 31062 Toulouse Cedex, France
2
Department of Physics, University of Cincinnati, Cincinnati, OH
45221-0011, USA
3
Institut de Physique Théorique, Université de Lausanne, 1015 Lausanne, Switzerland
Received:
6
July
2000
Published online: 15 October 2000
In order to understand the properties of Mott insulators with strong ground state orbital fluctuations, we study the zero temperature properties of the SU(4) spin-orbital model on a square lattice. Exact diagonalizations of finite clusters suggest that the ground state is disordered with a singlet-multiplet gap and possibly low-lying SU(4) singlets in the gap. An interpretation in terms of plaquette SU(4) singlets is proposed. The implications for LiNiO2 are discussed.
PACS: 75.10.Jm – Quantized spin models / 11.30.-j – Symmetry and conservation laws / 75.40.Mg – Numerical simulation studies
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2000
