Abstract

Magnetic field induced multiple non-Dirac nodal-lines are found to emerge in the triplet dispersion bands of a frustrated spin-1/2 antiferromagnetic model on the CaVO lattice. Plaquette and bond operator formalisms have been employed to obtain the triplet plaquette and bond excitations for two different parameter regimes in the presence of nearest and next-nearest-neighbor Heisenberg interactions based on the plaquette-resonating-valence-bond and dimerized ground states, respectively. In the absence of magnetic field a pair of six-fold degenerate nodal-loops with distinct topological feature is noted in the plaquette excitations. They are found to split into three pairs of two-fold degenerate nodal-loops in the presence of magnetic field. In the other parameter regime, system hosts two-fold degenerate multiple nodal-lines with a variety of shapes in the triplon dispersion bands in the presence of magnetic field. Ground state energy and spin gap have been determined additionally for the two regimes. Those nodal-lines are expected to be observed in the inelastic neutron scattering experiment on the frustrated antiferromagnet, CaV₄O₉.

Graphical abstract

中文翻译：

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沮丧的反铁磁体CaV 4 O 9的三重态激发中的磁场感应拓扑结线。

摘要

发现在CaVO晶格上沮丧的自旋1/2反铁磁模型的三重态色散带中出现了磁场感应的多个非狄拉克结线。在存在最接近和下一个近邻海森堡相互作用的情况下，已经根据质块-共振价键和二聚化基态，使用质块和键算子形式主义来获得两种不同参数方案的三重态质块和键激发。 。在没有磁场的情况下，在球拍激励中会注意到一对具有独特拓扑特征的六倍简并节点环。发现它们在存在磁场的情况下分裂为三对两倍简并的结环。在其他参数体制下，该系统在存在磁场的情况下，在三重色散带中具有多种形状的两倍简并的多条节点线。还为这两种方案确定了基态能量和自旋间隙。那些结线有望在沮丧的反铁磁体CaV的非弹性中子散射实验中观察到₄ O ₉。

图形概要