论文标题
磁性墙纸狄拉克费米子和拓扑磁性狄拉克绝缘子
Magnetic wallpaper Dirac fermions and topological magnetic Dirac insulators
论文作者
论文摘要
拓扑晶体绝缘子（TCI）可以托有异常的表面状态，该状态继承了保护块状拓扑的晶体对称性的特征。特别是，磁性晶体对称性的多样性表明具有不同表面特征的新型磁性TCI的潜力。在这里，我们提出了一个拓扑磁性狄拉克绝缘子（TMDI），其二维表面托有四倍的dirac费物，该dirac费物受到$ p'__c4mm $或$ p4'g'm $ $磁磁性壁纸组的保护。 TMDIS的批量拓扑受到对角线镜对称性的保护，这些对称性给出了表面狄拉克费米和受镜保护的铰链模式的手性分散。我们提出了针对TMDIS的候选材料，包括ND $ _4 $ TE $ _8 $ CL $ _4 $ o $ $ _ {20} $和DYB $ _4 $基于第一原则计算，并构建了使用proamagnetic父母的空间组来搜索TMDIS的一般方案。我们对TMDI的理论发现将促进对磁TCI的未来研究，并说明一种在磁性晶体中实现异常表面状态的独特方法。
Topological crystalline insulators (TCIs) can host anomalous surface states which inherits the characteristics of crystalline symmetry that protects the bulk topology. Especially, the diversity of magnetic crystalline symmetries indicates the potential for novel magnetic TCIs with distinct surface characteristics. Here, we propose a topological magnetic Dirac insulator (TMDI), whose two-dimensional surface hosts fourfold-degenerate Dirac fermions protected by either the $p'_c4mm$ or $p4'g'm$ magnetic wallpaper group. The bulk topology of TMDIs is protected by diagonal mirror symmetries, which give chiral dispersion of surface Dirac fermions and mirror-protected hinge modes. We propose candidate materials for TMDIs including Nd$_4$Te$_8$Cl$_4$O$_{20}$ and DyB$_4$ based on first-principles calculations, and construct a general scheme for searching TMDIs using the space group of paramagnetic parent states. Our theoretical discovery of TMDIs will facilitate future research on magnetic TCIs and illustrate a distinct way to achieve anomalous surface states in magnetic crystals.
