Šmejkal L, Železný J, Sinova J, Jungwirth T
Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, 162 53 Praha 6, Czech Republic.
Institut für Physik, Johannes Gutenberg Universität Mainz, D-55099 Mainz, Germany.
Phys Rev Lett. 2017 Mar 10;118(10):106402. doi: 10.1103/PhysRevLett.118.106402. Epub 2017 Mar 6.
Spin orbitronics and Dirac quasiparticles are two fields of condensed matter physics initiated independently about a decade ago. Here we predict that Dirac quasiparticles can be controlled by the spin-orbit torque reorientation of the Néel vector in an antiferromagnet. Using CuMnAs as an example, we formulate symmetry criteria allowing for the coexistence of topological Dirac quasiparticles and Néel spin-orbit torques. We identify the nonsymmorphic crystal symmetry protection of Dirac band crossings whose on and off switching is mediated by the Néel vector reorientation. We predict that this concept verified by minimal model and density functional calculations in the CuMnAs semimetal antiferromagnet can lead to a topological metal-insulator transition driven by the Néel vector and to the topological anisotropic magnetoresistance.
自旋轨道电子学和狄拉克准粒子是大约十年前独立兴起的凝聚态物理的两个领域。在这里，我们预测狄拉克准粒子可以通过反铁磁体中奈尔矢量的自旋轨道扭矩重新定向来控制。以CuMnAs为例，我们制定了允许拓扑狄拉克准粒子和奈尔自旋轨道扭矩共存的对称性标准。我们确定了狄拉克带交叉的非对称晶体对称性保护，其开启和关闭切换由奈尔矢量重新定向介导。我们预测，在CuMnAs半金属反铁磁体中通过最小模型和密度泛函计算验证的这一概念可导致由奈尔矢量驱动的拓扑金属-绝缘体转变以及拓扑各向异性磁阻。
