Integration between magnetism and topology is an exotic phenomenon in condensed-matter physics. Here, we propose an exotic phase named topological crystalline antiferromagnetic state, in which antiferromagnetism intrinsically integrates with nontrivial topology, and we suggest such a state can be realized in tetragonal FeS. A combination of first-principles calculations and symmetry analyses shows that the topological crystalline antiferromagnetic state arises from band reconstruction induced by pair checker-board antiferromagnetic order together with band-gap opening induced by intrinsic spin-orbit coupling in tetragonal FeS. The topological crystalline antiferromagnetic state is protected by the product of fractional translation symmetry, mirror symmetry, and time-reversal symmetry, and present some unique features. In contrast to strong topological insulators, the topological robustness is surface-dependent. These findings indicate that non-trivial topological states could emerge in pure antiferromagnetic materials, which sheds new light on potential applications of topological properties in fast-developing antiferromagnetic spintronics.
Competing Mechanisms between Dislocation and Phase Transformation in Plastic Deformation of Single Crystalline Yttria-Stabilized Tetragonal Zirconia Nanopillars
Bi-collinear antiferromagnetic order in the tetragonal $α$-FeTe
通过第一性原理电子结构计算，我们发现PbO型四配体$α$的基态处于双共线反铁磁态，其中Fe的局域磁矩（$\sim2.5μ_B$）沿Fe正方晶格的一个对角线方向是铁磁有序的，而沿另一个对角线方向是反铁磁有序的.这种双共线顺序是由Te $5p$带介导的最近、次最近和次次最近邻超交换相互作用$J_1$、$J_2$和$J_3$之间的相互作用产生的。相反，$α$的基态是共线反铁磁序，与LaFeAsO和BaFe $_2$ As $_2$相似.
Step-edge assisted large scale FeSe monolayer growth on epitaxial Bi2Se3 thin films
铁硫族化物非常规超导体的兴趣是强烈的后，FeSe的临界温度被报道提高了一个以上的数量级的单层限制在界面处的绝缘氧化物衬底。在包括FeSe与拓扑绝缘体的界面的异质结构中，预测会出现例如{ \it拓扑超导性}形式的另外的感兴趣的物理现象。到目前为止，铁硫系单分子膜的超导特性主要是通过局域扫描隧道谱实验来研究的，局域扫描隧道谱实验可以检测到态密度中的赝能隙，作为库珀配对的指示。由于难以生长具有均匀材料性质的薄膜，因此很少报道可以证明或证伪超导相的直接宏观输运性质。在这里，我们报告了一个有前途的生长方法，以制造单层厚FeSe分子束外延生长的Bi $_2$ Se $_3$拓扑绝缘体薄膜的连续地毯。与先前使用原子级平坦解理的块体Bi $_2$ Se $_3$晶体表面的工作相比，我们观察到高台阶边缘密度（平台宽度约10 nm）对MBE生长的Bi $_2$ Se $_3$衬底的强烈影响，这显著地促进了具有小的四方晶体畸变的聚结FeSe畴的生长，而不损害下面的Bi $_2$ Se $_3$晶体结构。
Donostia International Physics Center（圣塞巴斯蒂安国际物理中心）；University of the Basque Country (UPV/EHU)（巴斯克大学）；Goethe-Universität Frankfurt（法兰克福歌德大学）；Université de Sherbrooke（舍布鲁克大学）；RIKEN iTHEMS（理化学研究所 iTHEMS）；Center for Emergent Matter Science, RIKEN（理化学研究所 emergent matter science 中心）；Regroupement Québécois sur les Matériaux de Pointe (RQMP)（魁北克前沿材料研究联盟）
Symmetry Enhanced Unconventional Spin Current Anisotropy in a Collinear Antiferromagnet
University of Gothenburg（哥德堡大学）；Research Institute of Electrical Communication, Tohoku University（东北大学电气通信研究所）；Indian Institute of Technology Delhi（德里印度理工学院）
