“…The physical nature of valley topological edge states is mainly related to the following effects, such as the quantum Hall effect, [18,19] Floquet topological insulators, [20,21] quantum spin Hall effect, [18,21,22] or quantum valley Hall effect. [22,23] An external magnetic field was initially employed to break the time-reversal symmetry, [24,25] and then spatial inversion symmetry breaking was proposed to obtain the effects above.…”