Bismuth Atomic Chains in Zeolite Channels as One-Dimensional Topological Insulators

One-dimensional topological insulators have been theoretically predicted within the Su- Schrieffer-Heeger and Bernevig-Hughes-Zhang (BHZ) frameworks, but no robust mate- rials realization exists. We predict that single-atom bismuth chains confined in zeolite channels constitute one-dimensional topological insulators with Z_2 = 1, driven by s-p orbital band inversion rather than SSH-type dimerization. The large crystal field inver- sion in Bi (M = 1.2 eV < 2t = 1.6 eV, giving M/2t = 0.75) places the system deep in the topological phase. Atomic spin-orbit coupling of lambda_SOC = 600 meV opens a topological gap of 50-200 meV at the band inversion point, while the competing Peierls dimerization instability produces a gap of only 1.24 meV — a dominance ratio of 569:1. Exact diagonalization of finite chains confirms exponentially localized edge states at the chain termini for chains as short as 10 unit cells. We compute the BHZ parameters across seven zeolite frameworks with channel diameters from 5.5 to 7.4 Angstrom and find that all channels wider than 3.5 Angstrom support the topological phase, with gaps increasing monotonically with channel diameter. Predicted gaps exceeding 150 meV would enable room-temperature topological protection (k_B T = 26 meV at 300 K), using commercially available zeolites and elemental bismuth.