Fig. 4: Open lattice and edge states.
From: Non-Abelian Bloch oscillations in higher-order topological insulators
a Open lattice in the atomic limit respecting mirror Mx,y and C4 symmetries. Highlighted in blue the edge sites displaying zero modes and in red the unit cell for the stripe geometry. b Energy spectrum obtained by imposing periodic boundary conditions along \(\hat{y}^{\prime}\) and J1 = 0.8J2. Each edge hosts a pair of detached helical edge modes. c Positive energy edge state for \({k}_{y^{\prime} }={k}_{{\mathcal{C}}}=\pi /2\).
