Spin anisotropy of Seff=1/2 triangular rare-earth based antiferromagnets

In quantum magnetism significant efforts have been devoted to the search for new quantum states. In particular the Quantum Spin Liquid (QSL) state on the triangular lattice has attracted a lot of attention as it shows intriguing collective phenomena such as fractionalized excitations. We have synthesized a large amount (5g) of polycrystalline samples of four members of the Ba6R2Ti4O17 (BaRTiO) Seff=1/2 triangular antiferromagnets family, with R = Yb, Nd, Er and Y. Here, we propose to use neutron spectroscopy to determine the spin anisotropy of the effective S=1/2 triangular antiferromagnets of this family. The single-ion anisotropy is a crucial parameter to determine in order to confront the observed ground states to the theoretical phase diagram of the anisotropic triangular model, where QSL states have been predicted.

量子磁学领域中，人们已投入大量精力探索新型量子态。尤其值得注意的是，三角晶格上的量子自旋液体（Quantum Spin Liquid, QSL）态因其展现出分数量子激发等引人入胜的集体现象而备受关注。我们合成了大量（5克）多晶样品，这些样品属于Ba6R2Ti4O17（BaRTiO）家族中四个成员的有效自旋S=1/2三角反铁磁体，其中R为Yb、Nd、Er和Y。在此，我们提议利用中子光谱学测定该家族中有效自旋S=1/2三角反铁磁体的自旋各向异性。单离子各向异性是一个关键参数，确定该参数有助于将观测到的基态与各向异性三角模型的理论相图进行对比，而该模型中已预测存在QSL态。