Wieser R, Vedmedenko E Y, Wiesendanger R
Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Universität Hamburg, Jungiusstrasse 11, Hamburg, Germany.
Phys Rev Lett. 2008 Oct 24;101(17):177202. doi: 10.1103/PhysRevLett.101.177202. Epub 2008 Oct 21.
The quantized stationary spin wave modes in one-dimensional antiferromagnetic spin chains with easy axis on-site anisotropy have been studied by means of Landau-Lifshitz-Gilbert spin dynamics. We demonstrate that the confined antiferromagnetic chains show a unique behavior having no equivalent, neither in ferromagnetism nor in acoustics. The discrete energy dispersion is split into two interpenetrating n and n' levels caused by the existence of two sublattices. The oscillations of individual sublattices as well as the standing wave pattern strongly depend on the boundary conditions. Particularly, acoustical and optical antiferromagnetic spin waves in chains with boundaries fixed (pinned) on different sublattices can be found, while an asymmetry of oscillations appears if the two pinned ends belong to the same sublattice.
利用朗道-里夫希茨-吉尔伯特自旋动力学方法研究了具有易轴在位各向异性的一维反铁磁自旋链中的量子化稳态自旋波模式。我们证明，受限反铁磁链表现出一种独特的行为，这种行为在铁磁性和声学中都没有与之等效的情况。由于存在两个子晶格，离散的能量色散被分裂成两个相互贯穿的n和n'能级。各个子晶格的振荡以及驻波模式强烈依赖于边界条件。特别地，可以在边界固定（钉扎）在不同子晶格上的链中发现声学和光学反铁磁自旋波，而如果两个钉扎端属于同一子晶格，则会出现振荡不对称的情况。
