Fig. 3: Chiral hinge states of odd-layer photonic AXI.
From: Photonic axion insulator with non-coplanar chiral hinge transport
a Schematic of chiral hinge transport and its projections on different planes. Both the bottom and top layers are A-layer. Blue (green) arrow lines indicate energy flow along the positive (negative) directions of axes. All twelve hinges are labeled, i.e., C1-C6 chiral hinges and T7-T12 trivial hinges in this case. b Calculated projected band structures. Blue and green dots represent the corresponding chiral hinges. Black dots denote the projected bulk and surface states (shadow regions). c Measured dispersions of hinge states. Color scale represents the intensity. White dashed lines enclose the frequency window of the complete bulk and surface bandgap. For comparison, under the same color bar, the trivial hinge states (lower panels) are enlarged twice or thirty times (white numbers), corresponding to their chiral counterparts.
