Rashba Spin-Orbit Coupling Induced Topological Phases Transition in Honeycomb Nanoribbon Heterojunction

Abstract: We explore the emergence of non-trivial topological phases arising from the interplay between structural geometry and the spin degree of freedom. Our system is a honeycomb nanoribbon heterostructure with armchair edges, consisting of a central Rashba spin-orbit coupled (SOC) region sandwiched between two pristine armchair nanoribbons. As the strength of Rashba SOC is increased, topological edge states exhibit at the interface between the Rashba SOC and pristine armchair honeycomb nanoribbon (ANR), and these edge states remain robust under edge perturbations. In addition, we find that for a finite width ANR, Rashba SOC can open/close a gap depending on its strength, which leads to a topological phase transition. This work provides an alternative perspective on how Rashba SOC influences topological properties.