セミナー情報

We study the ordering of the classical antiferromagnetic Heisenberg model on the triangular lattice with the next-nearest-neighbor (or the third-neighbor) interaction under magnetic fields by means of a mean-field analysis and a Monte Carlo simulation. When further-neighbor interactions become dominant, the ground state in zero magnetic field takes an incommensurate helical spin structure, which has three-fold degeneracy associated with three equivalent directions of the wavevector on the triangular lattice. We show that not only a simple single-Q state but also a variety of multiple-Q states, including the so-called "skyrmion-lattice" state, are stabilized under applied magnetic fields.