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The quadrupolar phases of the S=1 bilinear-biquadratic Heisenberg model on the triangular lattice

A. Laeuchli·F. Mila·K. Penc
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Abstract

Using mean-field theory, exact diagonalizations and SU(3) flavour theory, we have precisely mapped out the phase diagram of the S=1 bilinear-biquadratic Heisenberg model on the triangular lattice in a magnetic field, with emphasis on the quadrupolar phases and their excitations. In particular, we show that ferroquadrupolar order can coexist with short-range helical magnetic order, and that the antiferroquadrupolar phase is characterized by a remarkable 2/3 magnetization plateau, in which one site per triangle retains quadrupolar order while the other two are polarized along the field. Implications for actual S=1 magnets are discussed.

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A. Laeuchli, F. Mila, K. Penc. 2006-08-23. The quadrupolar phases of the S=1 bilinear-biquadratic Heisenberg model on the triangular lattice. https://doi.org/10.1103/physrevlett.97.087205

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