Aharonov-Bohm interference of topological hinge states

The transport response of topological surface states in strong topological insulators has undergone extensive investigation, yet the behavior of topological hinge modes remains enigmatic. Here, we uncover phase-coherent transport facilitated by the topological hinge states in a higher-order topological insulator. These conducting hinge states reside within the insulating bulk and surface, both gapped across the entire Brillouin zone. Our magnetoresistance measurements reveal pronounced h/e periodic (where h denotes Planck’s constant and e represents the electron charge) Aharonov–Bohm oscillation. Notably, the observed periodicity, which directly reflects the enclosed area of phase-coherent electron propagation, matches the area enclosed by the sample hinges. Furthermore, the h/e oscillations evolve as a function of magnetic field orientation, following the interference paths along the hinge modes allowed by topology and symmetry. These findings offer compelling evidence for the quantum interference phenomena arising from electron motion around the hinges.