Realization of helical edge transport in a magnetic topological insulator bilayer

Various quantum Hall systems are ideal platforms for investigating exotic transport phenomena. Here we construct a bilayer structure consisting of two magnetic topological insulator thin films with different coercivity. When the edge states of the two layers are tuned by varying the magnetic field, a synthetic quantum spin Hall phase with helical edge states can be realized. The robustness of this phase can be confirmed by multi-terminal transport measurement.