Here, we present microscopic evidence of the persistence of uniaxial $A$-type antiferromagnetic order to the surface layers of ${\mathrm{MnBi}}_2{\mathrm{Te}}_4$ single crystals using magnetic force microscopy. Our results reveal termination-dependent magnetic contrast across both surface step edges and domain walls, which can be screened by thin layers of soft magnetism. The robust surface $A$-type order is further corroborated by the observation of termination-dependent surface spin-flop transitions, which have been theoretically proposed decades ago. Our results not only provide key ingredients for understanding the electronic properties of the antiferromagnetic topological insulator ${\mathrm{MnBi}}_2{\mathrm{Te}}_4$, but also open a new paradigm for exploring intrinsic surface metamagnetic transitions in natural antiferromagnets.

中文翻译：

---

反铁磁拓扑绝缘子MnBi_ {2} Te_ {4}的表面具有稳健的A型有序和自旋跃迁。

在这里，我们提出了单轴持续性的微观证据 $\mathrm{一种}$型反铁磁令的表面层 ${\mathrm{锰铋}}_2{特}_4$使用磁力显微镜检查单晶。我们的研究结果揭示了跨表面台阶边缘和畴壁的端接相关的磁性对比，可以通过薄薄的软磁性来屏蔽。坚固的表面$\mathrm{一种}$理论上已经提出了终止相关的表面自旋跃迁转变，这进一步证实了这种类型的顺序。我们的结果不仅为了解反铁磁拓扑绝缘体的电子特性提供了关键要素${\mathrm{锰铋}}_2{特}_4$，也为探索天然反铁磁体中固有的表面亚磁跃迁开辟了新的范式。