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arXiv 1209.6091cond-mat.str-elcond-mat.other
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阻挫蜂窝反铁磁体中的Plaquette-RVB态

Plaquette-RVB state in the Frustrated Honeycomb Antiferromagnet

R. Ganesh, Satoshi Nishimoto, Jeroen van den Brink

摘要:

我们研究了蜂窝格子$J_1-J_2$模型中次近邻相互作用引起的格片-RVB(pRVB)态。从退耦六边形的极限出发,我们发展了一种元胞算符方法来描述pRVB态及其低能激发。我们的计算澄清了假定的pRVB态必然具有f-波对称性-元格波函数是凯库莱结构的反对称组合。我们估计了作为$J_2/J_1$的函数的元格有序振幅、基态能量和自旋能隙。pRVB状态在$J_2/J_1 \sim 0.25$附近最稳定。我们确定的波矢量的最低三重激发,这可以使用精确对角化或DMRG研究进行验证。当$J_2$被约化时,我们可以有一个非限定的量子相变(QPT)或一个一阶跃迁到Néel态。当$J_2$增加时,我们推测系统经历一级相变,进入打破晶格转动对称的状态。

英文摘要:

We study the proposed plaquette-RVB (pRVB) state in the honeycomb lattice $J_1-J_2$ model with frustration arising from next-nearest neighbour interactions. Starting with the limit of decoupled hexagons, we develop a plaquette operator approach to describe the pRVB state and its low energy excitations. Our calculation clarifies that the putative pRVB state necessarily has f-wave symmetry - the plaquette wavefunction is an antisymmetric combination of the Kekulé structures. We estimate the plaquette ordering amplitude, ground state energy and spin gap as a function of $J_2/J_1$. The pRVB state is most stable around $J_2/J_1 \sim 0.25$. We identify the wavevectors of the lowest triplet excitations, which can be verified using exact diagonalization or DMRG studies. When $J_2$ is reduced, we can have either a deconfined Quantum Phase Transition (QPT) or a first-order transition into a Néel state. When $J_2$ is increased, we surmise that the system undergoes a first order phase transition into a state which breaks lattice rotational symmetry.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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