Aharonov-Bohm Beating Induced by Coexisting Topological Surface States and 2DEG in Sb-Doped Bi₂Se₃ Nanowires.

Abstract

We report the observation of beating Aharonov-Bohm (AB) conductance oscillations in Sb-doped Bi₂Se₃ nanowires and attribute their origin to the quantum interference between topological surface states (TSSs) and a coexisting two-dimensional electron gas (2DEG). The interference of trajectories encircling TSSs and a 2DEG generates a characteristic beating envelope and regularly spaced satellite peaks in the Fourier spectra. Our temperature-dependent analysis confirms that these satellite peaks arise from coherent multiple-electron circulations along the nanowire perimeter. Crucially, we demonstrate that while the beating envelope and relative amplitudes evolve continuously for varying back-gate voltages, the AB frequencies remain insensitive, supporting their geometric origin. Our theoretical simulations successfully reproduce these features, supporting the idea that the AB beating originates from the dual channels. Our findings provide evidence for the coexistence of topological and trivial states in topological-insulator nanowires and highlight their interplay as a route to engineering interference in topological materials.