Epitaxial thin films of CuMnAs have recently attracted attention due to their potential to host relativistic antiferromagnetic spintronics and exotic topological physics. Here we report on the structural and electronic properties of a tetragonal CuMnAs thin film studied using scanning tunneling microscopy (STM) and density functional theory (DFT). STM reveals a blend of surface domains corresponding to two kinds of As-terminated surface reconstructions, and both domains show the expected semi-metallic behavior. An unexpected zigzag step edge surface reconstruction is observed with emerging electronic states below the Fermi energy. DFT calculations indicate that the step edge reconstruction can be attributed to an As deficiency that results in changes in the density of states of the remaining As atoms at the step edge. Our work provides a detailed understanding of the surface structure and step edges on the CuMnAs thin film, enabling in-depth studies of its topological properties and magnetism.

中文翻译：

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外延半金属CuMnAs薄膜表面的新兴边缘态

CuMnAs 的外延薄膜最近因其承载相对论反铁磁自旋电子学和奇异拓扑物理学的潜力而受到关注。在这里，我们报告了使用扫描隧道显微镜 (STM) 和密度泛函理论 (DFT) 研究的四方 CuMnAs 薄膜的结构和电子特性。STM 揭示了对应于两种 As 终止表面重建的表面域的混合，并且两个域都显示出预期的半金属行为。在费米能量以下的新兴电子态中观察到了意想不到的锯齿形台阶边缘表面重建。DFT 计算表明阶梯边缘重建可归因于 As 缺陷，导致阶梯边缘剩余 As 原子的状态密度发生变化。