Ring-exchange interaction in doubly degenerate orbital system

Abstract

Ring-exchange (RE) interaction in Mott insulator with doubly degenerate $e_g$ orbitals is studied. Hamiltonian for the RE interaction is derived by the perturbational calculation. A remarkably weak RE interaction destroys the orbital order caused by the order-by-fluctuation mechanism in the nearest-neighbor exchange-interaction model. A long range order of magnetic octupole moment, i.e. complex orbital wave functions, appears. Competition between octupole and quadrupole interactions strongly suppresses ordered moments.

5 pages, 5 figures

References in corpus (5)

• "Deconfined" quantum critical points
• Antiferromagnetic to valence-bond-soild transitions in two-dimensional SU(N) Heisenberg models with multi-spin interactions
• Orbital ordering and frustration of $p$-band Mott-insulators
• Orbital order in classical models of transition-metal compounds
• Neel order, ring exchange and charge fluctuations in the half-filled Hubbard model

Cited by in corpus (1)

• Dynamical Jahn-Teller Effect in Spin-Orbital Coupled System