セミナー情報

原子力機構・兵県大合同物性コロキウム(第79回)

日時: 平成23年12月13日(火) 16:00〜
Date and time: 13th Dec. (Tue.) 16:00〜
場所: SPring-8, 萌光館
Place: SPring-8, "HOUKOUKAN" seminar room
Title: Multiple-Q states and skyrmion lattice of the triangular-lattice Heisenberg antiferromagnet under magnetic fields
講演者: 大久保 毅 氏(大阪大学・理学研究科・宇宙地球)
Speaker: Dr. Tsuyoshi Okubo (Osaka University)
Abstract:

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.