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arXiv 0905.3385cond-mat.mes-hallcond-mat.str-el
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kagome晶格上的拓扑绝缘体

Topological insulator on the kagome lattice

H. -M. Guo, M. Franz

摘要:

在二维的可果美晶格中,流动的电子形成狄拉克半金属,类似于石墨烯。当晶格和自旋对称性被各种周期性扰动打破时,这种半金属会产生有趣的非磁性绝缘相。这些包括具有非平凡Z_2不变和鲁棒无隙边缘态的二维拓扑绝缘体,以及二聚和三聚的“Kekule”绝缘体。后两个是拓扑平凡的,但凯库勒相具有复杂的序参量分数带电涡激发。一个电荷密度波耦合到狄拉克费米子作为一个有效的轴向规范场。

英文摘要:

Itinerant electrons in a two-dimensional Kagome lattice form a Dirac semi-metal, similar to graphene. When lattice and spin symmetries are broken by various periodic perturbations this semi-metal is shown to spawn interesting non-magnetic insulating phases. These include a two-dimensional topological insulator with a non-trivial Z_2 invariant and robust gapless edge states, as well as dimerized and trimerized `Kekule' insulators. The latter two are topologically trivial but the Kekule phase possesses a complex order parameter with fractionally charged vortex excitations. A charge density wave is shown to couple to the Dirac fermions as an effective axial gauge field.

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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