Chernyshev A L, Zhitomirsky M E
Department of Physics, University of California, Irvine, California 92697, USA.
Phys Rev Lett. 2006 Nov 17;97(20):207202. doi: 10.1103/PhysRevLett.97.207202. Epub 2006 Nov 13.
Instability of the excitation spectrum of an ordered noncollinear Heisenberg antiferromagnet with respect to spontaneous two-magnon decays is investigated. We use a spin-1/2 antiferromagnet on a triangular lattice as an example and examine the characteristic long- and short-wavelength features of its zero-temperature spectrum within the 1/S approximation. The kinematic conditions are shown to be crucial for the existence of decays and for overall properties of the spectrum. The XXZ and the J-J generalizations of the model, as well as the role of higher-order corrections, are discussed.
研究了有序非共线海森堡反铁磁体激发谱相对于自发双磁振子衰变的不稳定性。我们以三角晶格上的自旋1/2反铁磁体为例，在1/S近似下研究其零温谱的特征长波和短波特性。运动学条件对于衰变的存在和谱的整体性质至关重要。讨论了该模型的XXZ和J-J推广以及高阶修正的作用。
