发表机构
Institute of Science Tokyo; RIKEN Center for Emergent Matter Science (CEMS); Toyota Physical and Chemical Research Institute（东京科学大学; 理化学研究所 新兴物质科学中心; 丰田物理化学研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过分子束外延技术实现了具有强自旋轨道耦合的新型EuIn₂Sb₂薄膜的外延稳定生长，证实其为轴子绝缘体和高阶拓扑绝缘体的理想候选材料，为磁性拓扑相研究提供了新平台。
AI 中文摘要
通式为EuA₂X₂的Eu三角晶格层状化合物因具有丰富的层状晶体结构及对应的磁性拓扑相而受到日益广泛的关注，这类相源于Eu的大磁矩与能量反转的A和X能带的共存。在EuA₂X₂家族中，EuIn₂Sb₂因具有更强的自旋轨道耦合，被预测会拥有稳定的轴子绝缘体和高阶拓扑绝缘体态，但尚未在实验中实现，包括其结构的确认。本研究采用分子束外延技术实现了EuIn₂Sb₂的外延稳定生长。结构表征显示，EuIn₂Sb₂薄膜基于独特的In在In上的堆叠方式，形成了一种不同于EuA₂X₂家族此前预测结构的新型三层结构。除了在奈尔温度TN=10.5K下的面内反铁磁有序外，EuIn₂Sb₂中更强的自旋轨道耦合以及增强的In-In杂化，使其成为轴子绝缘体和高阶拓扑绝缘体相的理想候选材料。这些结果确立了EuIn₂Sb₂作为EuA₂X₂家族的新成员，为探索这些磁性拓扑相提供了先进的平台。
英文摘要
Eu triangular lattice layer compounds described by the general formula EuA2X2 have attracted growing attention due to a wide range of layered crystal structures and corresponding magnetic topological phases, arising from the coexistence of large Eu magnetic moments and energetically inverted A and X bands. Among the EuA2X2 family, EuIn2Sb2 has been predicted to host robust axion insulator and higher-order topological insulator states by stronger spin-orbit coupling but has not been experimentally realized, including the structural identification. Here we report the epitaxial stabilization of EuIn2Sb2 by adopting the molecular beam epitaxy technique. Structural characterization reveals that EuIn2Sb2 films are based on a unique In-on-In stacking, forming a new trilayer structure distinct from previously predicted structures in the EuA2X2 family. In addition to the in-plane antiferromagnetic ordering at TN=10.5K, the stronger spin-orbit coupling and enhanced In-In hybridization in EuIn2Sb2 make it an ideal candidate of axion insulator and higher-order topological insulator phases. These results establish EuIn2Sb2 as a new member of the EuA2X2 family and offer an advanced platform for exploring these magnetic topological phases.
Comments19 pages, 4 figures
