When a two-dimensional $d$-wave altermagnet is grown on a substrate, the interplay of momentum-dependent spin splittings arising from altermagnetism and Rashba spin-orbit coupling gives rise to a nodal band structure with band degeneracies enforced by a $C_{4z}\mathcal{T}$ symmetry. If we break the $C_{4z}\mathcal{T}$ symmetry by an exchange field, the band degeneracies are found to be immediately lifted, leading to a topological band structure characterized by nontrivial strong and weak topological indices. Remarkably, both the strong topological index and the $Z_{2}$-valued weak topological indices depend sensitively on the direction of the exchange field. As a consequence of the bulk-defect correspondence, we find that the unique dependence of weak topological indices on the exchange field in this system dictates that the presence or absence of topological bound states at lattice dislocations also depends sensitively on the direction of the exchange field. When the substrate is an $s$-wave superconductor, we find that a similar dependence of band topology on the exchange field gives rise to field-sensitive dislocation Majorana zero modes. As topological dislocation bound states are easily detectable by scanning tunneling microscopy, our findings unveil a promising experimental diagnosis of altermagnetic materials among an ever growing list of candidates.
Stacking-Controlled Altermagnetism and Topological Magnons in Bilayer CrI$_3$
Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, State Key Laboratory of Optoelectronic Materials and Technologies, Institute of Neutron Science and Technology, School of Physics, Sun Yat-Sen University（中山大学物理学院中子科学与技术研究所光电材料与技术国家重点实验室磁电物理与器件广东省重点实验室）
Correlated topological band structures of the kagome altermagnets Mn$_3X$ ($X=$ Sn, Ge, Ga)
Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences（中国科学院物理研究所）；School of Physical Sciences, University of Chinese Academy of Sciences（中国科学院大学物理科学学院）；Institute of Quantum Materials and Physics, Henan Academy of Sciences（河南省科学院量子材料物理研究所）；Institute for Applied Physics, University of Science and Technology Beijing（北京科技大学应用物理学院）；Songshan Lake Materials Laboratory（松山湖材料实验室）
Thermally-driven reorientation of the Néel vector in altermagnetic MnTe
PSI Center for Neutron and Muon Sciences（瑞士保罗谢勒研究所中子与μ子科学中心）；Faculty of Mathematics and Physics, Charles University（布拉格查理大学数学与物理学院）；Institute of Physics, Czech Academy of Sciences（捷克科学院物理研究所）；Department of Condensed Matter Physics, Faculty of Science, Masaryk University（布尔诺马萨里克大学理学院凝聚态物理系）；School of Physics and Astronomy, University of Nottingham（诺丁汉大学物理与天文学学院）；PSI Center for Photon Science（瑞士保罗谢勒研究所光子科学中心）；Institut de Physique, École Polytechnique Fédérale de Lausanne（洛桑联邦理工学院物理研究所）
Critical Structural Parameter Determining Magnetic Phases in the Fe2Mo3O8 Altermagnet System
New Jersey Institute of Technology（新泽理工学院）；Rutgers University（罗格斯大学）；The University of Chicago（芝加哥大学）；University of Illinois at Chicago（伊利诺伊大学芝加哥分校）；Cornell University（康奈尔大学）；Brookhaven National Laboratory（布鲁克海文国家实验室）
