d¹⁰氧化物单层中的量子反常霍尔效应
Quantum Anomalous Hall Effect in $d^{10}$ Oxide Monolayers
中文总结 AI 辅助
本文提出M₂DO₆二维氧化物家族，通过阳离子脱嵌激活O-2p铁磁性，实现陈数为4的高陈数量子反常霍尔效应，为氧基磁性拓扑平台提供设计原则。
中文摘要 AI 辅助
量子反常霍尔效应（QAHE）源于磁有序与自旋轨道耦合的相互作用，可在无外磁场时打开拓扑非平庸带隙以容纳手性边缘态。迄今为止，QAHE的磁有序通常源自部分填充的过渡金属d轨道或关联驱动的莫尔带。本文提出一类实验上可实现的二维氧化物家族M₂DO₆（M=Zn、Cd；D=Se、Te），其可通过半填充O-2p轨道诱导的自发铁磁性实现QAHE。在M₂DO₆单层中，自旋极化的狄拉克点出现在K/K'谷及Γ-K/Γ-K'线上，C₃旋转对称性在第一布里渊区产生8个对称性相关的交叉点；经自旋轨道耦合打开带隙后，每个有质量狄拉克点贡献半陈数，形成陈数为4的高陈数QAHE相。本文确立阳离子脱嵌为激活氧化物中O-2p铁磁性的通用策略，该发现提供了从O-2p铁磁性实现QAHE的途径，并为超越传统d电子体系的氧基磁性拓扑平台提供了设计原则。
英文摘要
Quantum anomalous Hall effect (QAHE) arises from the interplay between magnetic order and spin-orbit coupling, which opens up a topologically nontrivial band gap to host chiral edge states in the absence of magnetic field. So far, magnetic order of QAHE usually originates from partially filled transition-metal $d$ orbitals or correlation-driven moiré bands. Here, we propose an experimentally accessible family of two-dimensional oxides, M$_2$DO$_6$ (M = Zn, Cd; D = Se, Te), that can realize QAHE from the half-filled O-$2p$ orbital induced spontaneous ferromagnetism. In M$_2$DO$_6$ monolayers, spin-polarized Dirac points appear at K/K$^{\prime}$ valleys and along $Γ$-K/$Γ$-K$^{\prime}$ lines. $C_3$ rotational symmetry then generates eight symmetry-related crossings in the first Brillouin zone. Upon gap opening by spin-orbit coupling, each massive Dirac point contributes half Chern number, resulting in a high-Chern-number QAHE phase with $\mathcal{C}=4$. We establish cation deintercalation as a general strategy to activate O-$2p$ ferromagnetism in oxides. Our finding provides a route to realize QAHE from O-$2p$ ferromagnetism and offers design principles applicable to oxygen-based magnetic topology platforms beyond conventional $d$-electron systems.
