The authors of the theoretical work say in their paper, Our work addresses the question: ‘Where does the, famously quantized, charge current flow in a Chern insulator?’
This question received considerable attention in the context of the quantum Hall effect, but the progress there has been hampered by the lack of local probes, and no consensus has emerged so far. The fundamental problem is the following: topological protection is excellent at hiding local information (such as the spatial distribution of the current),—a phenomenon that we call topological censorship.
Two recent experiments, which used local probes to determine the spatial current distribution in Chern insulator heterostructures (Bi, Sb)2Te3, have remedied the dearth of experimental data in the case of the anomalous quantum Hall effect. These experiments reached unexpected, albeit very different, conclusions. Here, we provide the theory explaining one of these experiments.