Spin Liquid phases in extended Kitaev model on the Honeycomb Lattice

日期:2019-04-18 阅读:618


The Kitaev model on the honeycomb lattice offers exactly soluble examples of both gapped and gapless quantum spin liquids (QSLs). In addition to the Kitaev (K) interaction, candidate Kitaev materials also possess Heisenberg (J) and off-diagonal symmetric (Gamma) couplings. We investigate the quantum spin-1/2 K-J-Gamma model on the honeycomb lattice by a variational Monte Carlo (VMC) method. In addition to the Kitaev spin liquid (KSL) phase, we find that there is one proximate Kitaev Spin Liquid (PKSL) phase, while the rest of the phase diagram contains different magnetically ordered states. The KSL is known as a gapless state with 2 Majorana cones and a (almost) gapped spin response. In contrast, the PKSL has 14 Majorana cones and a gapless spin response. In a magnetic field applied normal to the honeycomb plane, it realizes two of Kitaev's gapped chiral spin-liquid states, namely, a non-Abelian phase with Chern number 5 and an Abelian phase with Chern number 2. The experimental characters of the chiral spin liquids are their thermal Hall conductances. Our phase diagram provides a clue in understanding the physics of candidate Kitaev materials.



刘正鑫于2010年在香港科技大学获得博士学位,同年在清华大学高等研究院从事博士后研究并得到C.N. Yang Junior fellow的奖励。2012至2015年作为副研究员继续留在清华大学高等研究院工作。2015年加入中国人民大学物理系。刘正鑫的研究兴趣主要包括低维阻挫系统中的量子磁性,强相互作用系统中对称保护拓扑序的分类和物理实现,以及关联系统中的数值计算方法。目前主要关注自旋1/2的Kitaev材料以及大自旋系统中的量子自旋液体相。


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