Quantum Transport and Hinge-State Interference in Quasi-One-Dimensional Topological Insulators

The discovery of higher-order topological insulators (HOTIs) has broadened the understanding of topological phases beyond conventional edge and surface states [1–3]. Among these, the quasi one-dimensional compounds Bi₄X₄ (X = I, Br) have emerged as ideal platforms hosting robust, spin-polarized hinge states [4–10].

In this work, we investigate quantum transport in quasi-one-dimensional topological insulators of the Bi₄X₄ family using a tight-binding framework. We systematically analyze how hinge-state conductance is influenced by system size (length and thickness), temperature, magnetic field, relaxation time, and Fermi energy. By tuning these parameters, we observe the emergence, suppression, and modulation of hinge-state interference patterns [11]. We show that the two counter-propagating hinge channels localized at opposite edges can exhibit coherent interference, and the resulting conductance oscillations provide a direct signature of hinge-state coupling and phase coherence. Furthermore, we map the spatial distribution of wavefunction density over orbital and spin degrees of freedom to identify the transition from bulk dominated to hinge-dominated transport. Our results demonstrate that hinge-state transport remains robust up to moderate temperature and disorder scales but becomes sensitive to geometric confinement and magnetic flux. These findings suggest pathways to engineer tunable topological interference for quantum sensing and low-power electronic applications.