$Z_2$ flux binding to higher-spin impurities in the Kitaev spin liquid

Abstract

Stabilizing $Z_2$ fluxes in Kitaev spin liquids (KSLs) is crucial for both characterizing candidate materials and identifying Ising anyons. In this study, we investigate the effects of spin-$S$ magnetic impurities embedded in the spin-1/2 KSL. Utilizing exact diagonalization and density matrix renormalization group methods, we examine the impurity magnetization and ground-state flux sector with varying impurity coupling and spin size. Our findings reveal that impurity magnetization exhibits an integer/half-integer spin dependence, which aligns with analytical predictions, and a flux-sector transition from bound-flux to zero-flux occurs at low coupling strengths, independent of the impurity spin. Notably, for spin-3/2 impurities, we observe a reentrant bound-flux sector, which remains stable under magnetic fields. By considering fermionic representations of our spin Hamiltonian, we provide phenomenological explanations for the transitions. Our results suggest a novel way of binding a flux in KSLs, beyond the proposals of vacancies or Kondo impurities.

v2 to appear in npj Quantum Materials

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Cited by in corpus (4)

• Magnetic order through Kondo coupling to quantum spin liquids
• Hamiltonian-learning quantum magnets with non-local impurity tomography
• The nature of low-temperature spin-freezing in frustrated Kitaev magnets
• Majorana Signatures in Planar Tunneling through a Kitaev Spin Liquid