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arXiv · 1212.0932

Orbital Dzyaloshinskii-Moriya Exchange Interaction

Panjin Kim·Jung Hoon Han
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Abstract

Superexchange calculation is performed for multi-orbital band models with broken inversion symmetry. Orbital-changing hopping terms allowed by the symmetry breaking electric field lead to a new kind of orbital exchange term closely resembling the Dzyaloshinskii-Moriya spin exchange. The final superexchange Hamiltonian in two dimensions is expressed in terms of Gell-Mann matrices that break down as three spin operators and five nematic (quadrupole) order operators. Mean-field phase diagram exhibits a rich structure including anti-ferro-orbital, ferro-orbital, and both single and multiple spiral-orbital phases. Superexchange calculation for spinful, two-orbital model also strongly suggests a robust chiral-orbital order in the ground state.

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Panjin Kim, Jung Hoon Han. 2012-12-05. Orbital Dzyaloshinskii-Moriya Exchange Interaction. https://doi.org/10.1103/physrevb.87.205119

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