Z₂ flux binding to higher-spin impurities in the Kitaev spin liquid: mechanisms and implications

The stabilization of Z₂ fluxes in Kitaev spin liquids (KSLs) is essential for identifying Ising anyons and characterizing candidate materials. In this work [arXiv:2409.02190], we explore the influence of spin-S magnetic impurities embedded within a spin-1/2 KSL. By employing exact diagonalization and density matrix renormalization group (DMRG) methods, we study how impurity magnetization and the ground-state flux sector vary with impurity coupling and spin size changes. Our results show that impurity magnetization follows an integer or half-integer spin dependence, aligning with analytical predictions. Additionally, we observe a transition in the flux sector—from a bound-flux state to a zero-flux state—at low coupling strengths, which occurs independently of the impurity spin size. Remarkably, for spin-3/2 impurities, we find a reentrant bound-flux sector that remains stable even under the presence of magnetic fields. To provide insights into these transitions, we develop a minimal model based on Majorana fermions, offering a phenomenological interpretation of the flux-binding mechanisms. These findings suggest a new approach for binding fluxes in KSLs, expanding beyond prior methods involving vacancies or Kondo impurities.