Quantum behavior of orbitals in ferromagnetic titanates: novel orderings and excitations.
نویسندگان
چکیده
We investigate the collective behavior of orbital angular momentum in the spin ferromagnetic state of a Mott insulator with t(2g) orbital degeneracy. The frustrated nature of the interactions leads to an infinite degeneracy of classical states. Quantum effects select four distinct orbital orderings. Two of them have a quadrupolar order, while the other states show in addition weak orbital magnetism. Specific predictions are made for neutron scattering experiments which might help to identify the orbital order in YTiO3 and to detect the elementary orbital excitations.
منابع مشابه
Theory of orbital state and spin interactions in ferromagnetic titanates
A spin-orbital superexchange Hamiltonian in a Mott insulator with t2g orbital degeneracy is investigated. More specifically, we focus on a spin ferromagnetic state of the model and study a collective behavior of orbital angular momentum. Orbital order in the model occurs in a nontrivial way—it is stabilized exclusively by quantum effects through the order-from-disorder mechanism. Several energe...
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ورودعنوان ژورنال:
- Physical review letters
دوره 89 16 شماره
صفحات -
تاریخ انتشار 2002