论文标题
二维假蛋白-1狄拉克绝缘子中的异常间隙边缘状态
Anomalous in-gap edge states in two-dimensional pseudospin-1 Dirac insulators
论文作者
论文摘要
载有平坦带的量子材料，例如伪蛋白-1晶格和魔法扭曲的双层石墨烯，可以表现出巨大的新物理现象，包括非常规超导性，轨道铁磁性和Chern绝缘行为。我们报告了一种令人惊讶的电子间隙边缘状态在pseudospin-1材料中，而无需传统的带反转拓扑相变或通过外部磁性类型的相互作用引入磁性。特别地，我们发现，在二维间隙（绝缘）大型自旋-1准颗粒的狄拉克系统中，间隙边缘模式只能通过应用于有限域的{\ em em静电电势}出现。与这些非常规的边缘模式相关的是明显的域壁旋转纹理的自发形成，它们在域边界的两侧都表现出平面外旋转角动量锁定的特征，尽管缺乏明确的拓扑来源，但在边界边界的两侧都表现出非常牢固的耐心。间隙模式是正式的三组分evanescent Wave解决方案，类似于jackiw-rebbi类型的结合状态。这种模式由于以下物理原因而属于不同的类别：三组分旋转波函数，异常边界条件以及由外部标量电势引起的移位平坦谱带。不仅发现了基本重要性，而且还为使用传统的半导体门技术具有新兴的旋转纹理铺平了道路。使用连续狄拉克 - 韦尔模型的分析计算以及通过表征状态光谱和谐振隧道电导的局部密度来验证结果。
Quantum materials that host a flat band, such as pseudospin-1 lattices and magic-angle twisted bilayer graphene, can exhibit drastically new physical phenomena including unconventional superconductivity, orbital ferromagnetism, and Chern insulating behaviors. We report a surprising class of electronic in-gap edge states in pseudospin-1 materials without the conventional need of band-inversion topological phase transitions or introducing magnetism via an external magnetic type of interactions. In particular, we find that, in two-dimensional gapped (insulating) Dirac systems of massive spin-1 quasiparticles, in-gap edge modes can emerge through only an {\em electrostatic potential} applied to a finite domain. Associated with these unconventional edge modes are spontaneous formation of pronounced domain-wall spin textures, which exhibit the feature of out-of-plane spin-angular momentum locking on both sides of the domain boundary and are quite robust against boundary deformations and impurities despite a lack of an explicit topological origin. The in-gap modes are formally three-component evanescent wave solutions, akin to the Jackiw-Rebbi type of bound states. Such modes belong to a distinct class due to the following physical reasons: three-component spinor wave function, unusual boundary conditions, and a shifted flat band induced by the external scalar potential. Not only is the finding of fundamental importance, but it also paves the way for generating highly controllable in-gap edge states with emergent spin textures using the traditional semiconductor gate technology. Results are validated using analytic calculations of a continuum Dirac-Weyl model and tight-binding simulations of realistic materials through characterizations of local density of state spectra and resonant tunneling conductance.
