报告题目: Self-localized orbital induced flat band localization

报告人: 高锦华 副教授（华中科技大学）

报告时间：2018年9月26日（周三）下午14:30

报告地点：物理学院新楼5楼多功能厅

报告摘要:

Recently, flat bands in lattice have drawn lots of interest in the field of condensed matter physics. On one hand, kinetic energy is quenched, so that tiny interaction can induce electron correlated states. On the other hand, it is suggested that topological nontrivial flat band can give rise to  fractional quantum hall effect without magnetic field. Here,  we propose a new interference induced wave localization mechanism, which can produce perfect flat bands in periodic system, and is beyond the scope of tight binding lattice model. First, we numerically demonstrate that electron flat bands can arise in a quasi one dimensional electron waveguide with a designed confined potential.  Then, we propose the concept of self-localized orbital, which is reason for the flat bands in the electron waveguide.  Finally, we show that self-localized orbital induced flat band is a general phenomenon of wave, which can arise is any wave systems with proper boundary condition. We design a metallic waveguide array, and show that similar flat band localization can be readily realized and observed for electromagnetic wave.  The advantages of this kind of flat band are: (1) perfect flat bands can be achieved with this scheme; (2) the self-localized orbital, as well as the flat band structures, are highly controllable by adjusting the local geometry of the confinement potential.

报告人简介：

高锦华，2008年在中科院物理所取得博士学位，2009—2013年在香港大学从事博士后研究， 2013年起在华中科技大学物理学院工作。长期以来一直从事凝聚态理论的研究， 主要关注介观系统的物性研究。 在拓扑绝缘体中的磁性，介观系统中的超导，石墨烯系统中的关联效应等方面做出了一些有特色的研究工作。 已在国际前沿杂志上发表论文20余 篇， 其中Phys. Rev. Lett. 1 篇， Phys. Rev. B 14 篇。

邀请人：余睿教授