Fig. 3: Eigenfrequencies and eigenstates of the finite-sized network.

a The network configuration. b The complex eigenfrequency spectra of the sample in a (blue points), the x-PBC/y-OBC supercells in Fig. 2c (black solid points) and the x-OBC/y-PBC supercells in Fig. 2e (black dashed points). The gray zone represents the gap of the bulk continuum. c–f The field patterns for the eigenstates labeled from (i) to (iv) in b. Patterns (i), (ii), (iii) and (iv) are corresponding to the HSTE corner state c, the bulk state d, the corner state originating from the non-chiral edge state at the upper edge e and the non-chiral edge state at the lower edge f, respectively.