A flat band in fermionic system is a dispersionless single-particle state with a diverging effective mass and nearly zero group velocity. These flat bands are expected to support exotic properties in the ground state, which might be important for a wide range of promising physical phenomena. For many applications, it is highly desirable to have such states in Dirac materials, but so far they have been reported only in some nonmagnetic Dirac systems. In this paper, we propose a realization of topologically protected spin-polarized flat bands generated by domain walls in planar magnetic topological insulators. Using first-principles material design, we suggest a family of intrinsic antiferromagnetic topological insulators with an in-plane sublattice magnetization and high Néel temperature. Such systems can host domain walls in a natural manner. For these materials, we demonstrate the existence of spin-polarized flat bands in the vicinity of the Fermi level and discuss their properties and potential applications.

中文翻译：

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反铁磁拓扑绝缘体中畴壁诱导的自旋极化平带

费米系统中的平带是无色散的单粒子状态，具有发散的有效质量和几乎为零的群速度。预计这些平坦带将支持基态的奇异特性，这对于广泛的有前途的物理现象可能很重要。对于许多应用，非常希望在 Dirac 材料中具有这种状态，但到目前为止，它们仅在一些非磁性 Dirac 系统中被报道。在本文中，我们提出了由平面磁性拓扑绝缘体中的畴壁产生的拓扑保护的自旋极化平带的实现。使用第一性原理材料设计，我们提出了一系列具有面内亚晶格磁化和高 Néel 温度的本征反铁磁拓扑绝缘体。这样的系统可以以自然的方式托管域墙。