Fig. 2: Calculations on finite lattices in topological and trivial phases.
From: Observation of an acoustic octupole topological insulator
a–c Calculated eigenvalues of 5 × 5 × 5 lattices with different coupling configurations. d–f Sum of probabilities for different types of states in a–c, respectively. In a, there are four types of states (bulk, surface, hinge and corner), which are plotted in d. In b, all the states are bulk states (e). In c, there are three types of states (bulk, surface and hinge), which are plotted in f.
