2018/12/31 by Si-Si Wang, Yanyang Zhang, Yan-Yang Zhang +6 · 5 citations
Physics and Astronomy · #Axion #Chern–Simons theory #Condensed matter physics #Coupling (piping) #Electron #Materials science #Mesoscopic physics #Particle physics #Physics #Quantum #Quantum Hall effect #Quantum and electron transport phenomena #Quantum mechanics #Quantum, superfluid, helium dynamics #Topological Materials and Phenomena #cond-mat.mes-hall
paper · pdf · doi:10.1103/physrevb.99.125414
published in Physical review. B./Physical review. B 99(12) (American Physical Society) · 11 pages, 11 figures
openalex created_date 2018/12/22 · openalex publication_date 2019/03/11 · arxiv created 2019/03/12 · arxiv updated 2019/03/27 · openalex updated_date 2026/08/05
Quantum anomalous Hall (QAH) multilayers provide a platform for topological materials with high Chern numbers. We investigate the localization routes of bilayer QAH systems with Chern number C=2 during the process of increasing disorder, by numerical simulations on their quantum transport properties and the Chern-Simons axion coupling. The localization trajectories present richer behaviors than those in the monolayer with C=2. For example, there exists a stable intermediate state with C=1 before localization, which was always unstable in a monolayer. In some cases, this C=1 state is ``weak'' in the sense that its Hall plateau is hardly visible in a mesoscopic sample, but is still stable in the sense of renormalization group. The underlying physics is discussed. During the localization process, the Chern-Simons axion coupling shows a surprising peak which is even more remarkable in the large size limit. The physical origin of this peak is understood by a real-space analysis of the electronic states. As a result, the disordered QAH multilayers can be good candidates for this nontrivial magnetoelectric coupling mediated by orbital motions.