二维各向异性海森堡反铁磁体的基态性质

摘要

文章研究单离子各向异性影响下的二维正方晶格、自旋为1的阻挫海森堡反铁磁体的基态性质．利用自旋波方法，得到了在零温时该系统的奈尔相和共线相的子晶格磁化强度和基态能，发现了奈尔相－共线相转变的量子临界点依赖于单离子各向异性 D 以及次近邻反铁磁性耦合 J2与最近邻反铁磁耦合 J1的比值．在经典临界点 J2／J1＝0．5附近，当0≤D／J1≤0．03时系统存在一个中间无序顺磁相．自旋波的结果表明，在高于 J2／J1＝0．5区域，奈尔相－共线相转变是一级相变，发生在依赖于各向异性的临界线上．%The effect of the single-ion anisotropy on the ground-state properties of the spin-1 frustrated Heisen-berg antiferromagnet is investigated on a square lattice.The sublattice magnetizations as well as ground-state en-ergies of the system are obtained within the spin-wave method for the Neel and collinear phases at zero tempera-ture.It is found that the quantum critical points for the Neel and collinear phases are dependent on the single-ion anisotropy D and the ratio of next-nearest-neighbor antiferromagnetic coupling J2 to nearest-neighbor antifer-romagnetic coupling J1 .Near the classical point J2 /J1 =0.5,there is an intermediate disordered paramagnetic phase for 0≤D/J1 ≤0.03.Our spin-wave results show that a first order phase transition from the Neel phase to the collinear phase occurs at the anisotropy-dependence critical line above J2 /J1 =0.5.