Interplay of Electrode Coupling Engineering, Quasiperiodicity, and Magnetic Flux in Quantum Transport through a Su-Schrieffer-Heeger Ring

Abstract

We reveal that engineering electrode-coupling configurations can fundamentally reshape coherent transport phenomena in quasiperiodic quantum systems. Leveraging nonequilibrium Green's function theory, we systematically analyze charge and heat transport, as well as current fluctuations, in a magnetic-flux-threaded quasiperiodic Su-Schrieffer-Heeger ring with both symmetric and asymmetric multi-site reservoir couplings. Contrary to the conventional expectation that optimal transport is achieved near the homogeneous-hopping limit, our results reveal that multi-site lead coupling fundamentally reshapes the transport landscape, extending the regime of enhanced transport deep into the topological phase. Strikingly, asymmetric source-drain coupling induces a disorder-assisted conducting phase where quasiperiodic modulation enhances, rather than suppresses, charge and energy transport. Magnetic flux exerts a dual influence: it activates additional interference-mediated transmission channels that amplify transport while simultaneously suppressing the disorder-induced re-entrant conducting regime. Furthermore, we uncover a flux-driven migration of the optimal transport window with increasing disorder strength, shifting from the topological regime toward the trivial-hopping regime. This behavior highlights the intricate interplay among quasiperiodicity, dimerization, magnetic-flux-induced quantum interference, and the geometry of the system-reservoir coupling. Collectively, our findings position coupling engineering as a powerful paradigm for the rational control of nonequilibrium transport in quasiperiodic materials and chart a route toward quantum device configurations in which transport characteristics can be precisely tuned via the interplay of disorder, topology, and quantum interference.