Spin-orbit coupling engineered higher-order topology and flat bands in two-dimensional Su-Schrieffer-Heeger models
Phys. Rev. B 113, 155433 – Published 20 April, 2026
DOI: https://doi.org/10.1103/37gn-2g16
Abstract
We demonstrate how spin-orbit coupling (SOC) controls band topology and induces higher-order topological corner states in a two-dimensional Su-Schrieffer-Heeger (SSH) model. SOC lifts spin degeneracy and, when applied along both lattice directions, generates robust zero-energy corner states. By matching intracell (intercell) hopping strengths to their SOC counterparts, we produce topological flat bands, whose phases are classified by the charge polarization and verified through bulk-edge-corner correspondence. We propose an LC-circuit implementation and show numerically that the corner states remain strongly localized and robust in weak on-site disorder. These results establish SOC as a versatile tool for engineering higher-order topological phases and topological flat bands, offering an experimentally accessible route for realization in circuit systems.
