High spin systems with orbital degeneracy.

1 6 D ec 1 99 8 Elementary Excitations in Magnetically Ordered Systems with Orbital Degeneracy

The Holstein-Primakoff transformation is generalized to develop a quantum flavor wave theory for spin systems with orbital degeneracy. Elementary excitations of ordered ground states consist of spin, orbital , and spinorbital waves. Spin and spin-orbital waves couple to each other due to orbital anisotropy and Hund’s rule, resulting in new modes observable by inelastic neutron scattering. In th...

Spin and orbital Ti magnetism at LaMnO3/SrTiO3 interfaces.

In systems with strong electron-lattice coupling, such as manganites, orbital degeneracy is lifted, causing a null expectation value of the orbital magnetic moment. Magnetic structure is thus determined by spin-spin superexchange. In titanates, however, with much smaller Jahn-Teller distortions, orbital degeneracy might allow non-zero values of the orbital magnetic moment, and novel forms of fe...

Title Generalized valence bond state and solvable models for spin-1/2 systems with orbital degeneracy

SU(4) Theory for Spin Systems with Orbital Degeneracy

In many transitional metal oxides, the electron configuration on the metal ions has orbital degeneracy in addition to spin degeneracy. In these systems, the sign and magnitude of the spin-spin couplings depend on the orbital occupancy. This may result in interesting magnetic properties of the Mott insulating phase, and is believed to be relevant to unusual properties of many vanadium, titanium,...

The Ground State and Excitations of Spin Chain with Orbital Degeneracy

The one dimensional Heisenberg model in the presence of orbital degeneracy is studied at the SU(4) symmetric point by means of Bethe ansatz. Following Sutherland’s previous work on an equivalent model, we discuss the ground state and the low-lying excitations more extensively in connection to the spin systems with orbital degeneracy. We show explicitly that the ground state is a SU(4) singlet. ...