Lawler Michael J, Kee Hae-Young, Kim Yong Baek, Vishwanath Ashvin
Department of Physics, University of Toronto, 60 St. George Street, Toronto, Ontario, M5S 1A7, Canada.
Phys Rev Lett. 2008 Jun 6;100(22):227201. doi: 10.1103/PhysRevLett.100.227201. Epub 2008 Jun 2.
Recent experiments on the "hyperkagome" lattice system Na4Ir3O8 have demonstrated that it is a rare example of a three-dimensional spin-1/2 frustrated antiferromagnet. We investigate the role of quantum fluctuations as the primary mechanism lifting the macroscopic degeneracy inherited by classical spins on this lattice. In the semiclassical limit we predict, based on large-N calculations, that an unusual q[over -->]=0 coplanar magnetically ordered ground state is stabilized with no local zero modes that correspond to local deformations of the spin configurations. This phase melts in the quantum limit and a gapped topological Z2 spin liquid phase emerges. In the vicinity of this quantum phase transition, we study the dynamic spin structure factor and comment on the relevance of our results for future neutron scattering experiments.
最近对“超 Kagome”晶格系统 Na4Ir3O8 所做的实验表明，它是三维自旋 1/2 受挫反铁磁体的一个罕见例子。我们研究量子涨落作为消除该晶格上经典自旋所继承的宏观简并性的主要机制所起的作用。在半经典极限下，我们基于大 N 计算预测，一种不寻常的 q[上划线]=0 共面磁有序基态得以稳定，且不存在对应于自旋构型局部变形的局部零模。这个相在量子极限下熔化，一个有能隙的拓扑 Z2 自旋液体相出现。在这个量子相变附近，我们研究动态自旋结构因子，并对我们的结果与未来中子散射实验的相关性进行评论。
