We construct a dimerized square-octagon lattice model with the staggered magnetic fluxes threading plaquettes and find two types of topological states at half filling, i.e., the Chern insulator (CI) and the zero-Chern-number topological (ZCNT) states. The CI can be characterized on the basis of the chiral edge states and nonzero Chern number. Different from the CI, this ZCNT state hosts robust edge states with zero Chern number. Its topological nature can be identified by the quantized bulk polarization. More intriguingly, corner states emerge in this ZCNT state, even though its edge state is gapless. In addition, we present a phase diagram by tuning the dimerized hopping potential and the staggered fluxes. Our findings provide a promising approach to search more topological phases without time-reversal symmetry.

• Received 18 May 2022
• Revised 29 August 2022
• Accepted 20 September 2022

DOI:https://doi.org/10.1103/PhysRevB.106.125147