Fibonacci-Engineered Spin and Charge Thermoelectrics in a Long Range Su-Schrieffer-Heeger Chain: A Pathway to Giant Figure of Merit

Abstract

In this work, we present a novel investigation into the spin-dependent thermoelectric performance of an extended Su-Schrieffer-Heeger (SSH) model, showcasing for the first time how its intrinsic spin filtration mechanism can be strategically harnessed to function as an efficient spin thermoelectric generator. By introducing a Fibonacci-type aperiodic modulation in the onsite energies, we engineer a deterministic disorder that mimics realistic aperiodic systems and profoundly influences transport characteristics. Furthermore, we incorporate both nearest-neighbor (NN) and next-nearest-neighbor (NNN) hopping amplitudes with tunable cosine dependencies, enabling us to meticulously explore the intricate interplay between these hopping processes and its implications on thermoelectric behavior. Our analysis reveals a remarkable enhancement in the dimensionless thermoelectric figure of merit ZT for both charge and spin transport channels, under carefully optimized conditions. Notably, the spin thermoelectric response exhibits distinct advantages, opening a new frontier in the design of next-generation thermoelectric materials and devices. This qualitative study not only deepens our understanding of aperiodic topological systems but also establish a foundational framework for exploiting spin-based thermoelectricity in low-dimensional platforms.