Rashba Spin-Orbit Driven Topological Phase Transitions in Graphene Nanoribbon Heterostructures

TL;DR

This paper shows how Rashba spin-orbit coupling and geometric design in graphene nanoribbons can induce and control topological phases and interface states, enabling tunable topological properties.

Contribution

It introduces a mechanism for topological phase transitions driven by Rashba coupling in graphene nanoribbon heterostructures without lattice modifications.

Findings

Rashba coupling induces symmetry-protected interface states.

Topological phase transition occurs via gap closing and reopening.

Interface states are robust against edge perturbations.

Abstract

We demonstrate that the interplay between structural geometry and Rashba spin-orbit coupling generates nontrivial topological phases in honeycomb nanoribbon heterostructures. We consider an armchair nanoribbon in which a Rashba spin-orbit coupled region is embedded between pristine segments. Increasing the Rashba coupling induces symmetry-protected interface states localized at the junction between topologically distinct regions, which remain robust against edge perturbations. For finite ribbon widths, Rashba spin-orbit coupling drives a gap closing and reopening, signaling a topological phase transition without modifying the lattice structure. Our results reveal a mechanism by which interfacial geometry and spin-orbit interaction cooperatively engineer tunable topological states in graphene-based nanostructures.