Luo Ma
The State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-Sen University, Guangzhou, 510275, People's Republic of China.
J Phys Condens Matter. 2020 Nov 5;33(5). doi: 10.1088/1361-648X/abc1ff.
The two dimensional square lattice antiferromagnet with spin-orbit coupling and nonsymmorphic symmetry is recently found to be topological insulator (TI). We theoretically studied the Floquet states of the antiferromagnetic crystal with optical irradiation, which could be applicable in opto-spintronic. An optical irradiation with circular polarization induces topological phase transition into quantum Anomalous Hall phase with varying Chern number. At the phase boundaries, the Floquet systems could be semimetal with one, two or three band valleys. A linear polarized optical field induces effective antiferromagnetic exchange field, which change the phase regime of the TI. At the intersection of two phase boundaries, the bulk band structure is nearly flat along one of the high symmetry line in the first Brillouin zone, which result in large density of states near to the Fermi energy in bulk and nanoribbons.
最近发现，具有自旋轨道耦合和非点式对称性的二维正方晶格反铁磁体是拓扑绝缘体（TI）。我们从理论上研究了受光照射的反铁磁晶体的弗洛凯态，其可应用于光自旋电子学。圆偏振光照射会导致拓扑相变，进入具有变化陈数的量子反常霍尔相。在相边界处，弗洛凯系统可能是具有一个、两个或三个能带谷的半金属。线偏振光场会诱导有效的反铁磁交换场，从而改变TI的相区。在两个相边界的交点处，体能带结构在第一布里渊区的一条高对称线附近几乎是平的，这导致体材料和纳米带中靠近费米能的态密度很大。
