Phase Diagram of the Spin-Orbital model on the Square Lattice

• Main Authors: Zasinas, E, Sushkov, O. P, Oitmaa, J
• Format: Journal Article
• Language: English
• Published: 08-05-2001
• Subjects: Physics - Disordered Systems and Neural Networks; Physics - Materials Science; Physics - Mesoscale and Nanoscale Physics; Physics - Other Condensed Matter; Physics - Quantum Gases; Physics - Soft Condensed Matter; Physics - Statistical Mechanics; Physics - Strongly Correlated Electrons; Physics - Superconductivity
• DOI: 10.48550/arxiv.cond-mat/0105178

We study the phase diagram of the spin-orbital model in both the weak and
strong limits of the quartic spin-orbital exchange interaction. This allows us
to study quantum phase transitions in the model and to approach from both sides
the most interesting intermediate-coupling regime and in particular the
SU(4)-symmetric point of the Hamiltonian. It was suggested earlier by Li et al
[Phys.Rev.Lett. vol. 81, 3527 (1999)] that at this point the ground state of
the system is a plaquette spin-orbital liquid. We argue that the state is more
complex. There is plaquette order, but it is anisotropic: bonds in one
direction are stronger than those in the perpendicular direction. This order is
somewhat similar to that found recently in the frustrated J_1-J_2 Heisenberg
spin model.