Effects of spin vacancies on magnetic properties of the Kitaev-Heisenberg model

Abstract

We study the ground state properties of the Kitaev-Heisenberg model in a magnetic field and explore the evolution of spin correlations in the presence of non-magnetic vacancies. By means of exact diagonalizations, the phase diagram without vacancies is determined as a function of the magnetic field and the ratio between Kitaev and Heisenberg interactions. We show that in the (antiferromagnetic) stripe ordered phase the static susceptibility and its anisotropy can be described by a spin canting mechanism. This accounts as well for the transition to the polarized phase when including quantum fluctuations perturbatively. Effects of spin vacancies depend sensitively on the type of the ground state. In the liquid phase, the magnetization pattern around a single vacancy in a small field is determined, and its spatial anisotropy is related to that of non-zero further neighbor correlations induced by the field and/or Heisenberg interactions. In the stripe phase, the joint effect of a vacancy and a small field breaks the six-fold symmetry of the model and stabilizes a particular stripe pattern. Similar symmetry-breaking effects occur even at zero field due to effective interactions between vacancies. This selection mechanism and intrinsic randomness of vacancy positions may lead to spin-glass behavior.

13 pages, 10 figures

References in corpus (12)

• Mott Insulators in the Strong Spin-Orbit Coupling Limit: From Heisenberg to a Quantum Compass and Kitaev Models
• Quantum spin-liquid emerging in two-dimensional correlated Dirac fermions
• Spin-Liquid State in the S = 1/2 Hyperkagome Antiferromagnet Na4Ir3O8
• Exact results for spin dynamics and fractionization in the Kitaev Model
• Long range magnetic ordering in Na${}_2$IrO${}_3$
• Possible proximity of the Mott insulating Iridate Na2IrO3 to a topological phase: Phase diagram of the Heisenberg-Kitaev model in a magnetic field
• Effective spin model for the spin-liquid phase of the Hubbard model on the triangular lattice
• Disorder in a quantum spin liquid: flux binding and local moment formation
• Power-law spin correlations in a perturbed honeycomb spin model
• Universal alternating order around impurities in antiferromagnets
• Impurity-doped Kagome Antiferromagnet: A Quantum Dimer Model Approach
• Quantum magnets with weakly confined spinons: Multiple length scales and quantum impurities

Cited by in corpus (33)

• Relevance of the Heisenberg-Kitaev model for the honeycomb lattice iridates A_2IrO_3
• Generic spin model for the honeycomb iridates beyond the Kitaev limit
• Magnetic order in $\alpha$-RuCl${}_3$: a honeycomb lattice quantum magnet with strong spin-orbit coupling
• Direct evidence of a zigzag spin chain structure in the honeycomb lattice: A neutron and x-ray diffraction investigation on single crystal $\mathrm{N}{\mathrm{a}}_2\mathrm{Ir}{\mathrm{O}}_3$
• Finite-temperature phase diagram of the Heisenberg-Kitaev model
• Kitaev-Heisenberg-J2-J3 model for the iridates A2IrO3
• Honeycomb-lattice Heisenberg-Kitaev model in a magnetic field: Spin canting, metamagnetism, and vortex crystals
• Critical properties of the Kitaev-Heisenberg model
• Phase diagram and spin correlations of the Kitaev-Heisenberg model: Importance of quantum effects
• Effect of nonmagnetic dilution in honeycomb lattice iridates Na${}_2$IrO${}_3$ and Li${}_2$IrO${}_3$
• Destabilization of magnetic order in a dilute Kitaev spin liquid candidate
• Magnetism in spin models for depleted honeycomb-lattice iridates: Spin-glass order towards percolation
• Majorana-mediated spin transport without spin polarization in Kitaev quantum spin liquids
• Fidelity susceptibility in the two-dimensional spin-orbit models
• Signatures of a spin-1/2 cooperative paramagnet in the diluted triangular lattice of Y${}_2$CuTiO${}_6$
• Characterizing quantum criticality and steered coherence in the XY-Gamma chain
• Magnetic anisotropy of the alkali iridate Na${}_2$IrO${}_3$ at high magnetic fields: evidence for strong ferromagnetic Kitaev correlations
• Observation of a random singlet state in a diluted Kitaev honeycomb material
• Kitaev Quantum Spin Liquids
• Hidden Quasiparticles and Incoherent Photoemission Spectra in Na2IrO3
• Hole propagation in the Kitaev-Heisenberg model: From quasiparticles in quantum Neel states to non-Fermi liquid in the Kitaev phase
• Non-local spin correlation as a signature of Ising anyons trapped in vacancies of the Kitaev spin liquid
• A Kondo route to spin inhomogeneities in the honeycomb Kitaev model
• A Possible Fermi liquid in the lightly doped Kitaev spin liquid
• Vacancies in the Kitaev quantum spin liquids on the 3D hyper-honeycomb lattice
• Tuning into the Kitaev spin liquid phase:A spin model on the honeycomb lattice with two types of Heisenberg exchange couplings
• Topological magnons in one-dimensional ferromagnetic Su-Schrieffer-Heeger model with anisotropic interaction
• Perturbed Kitaev model: excitation spectrum and long-ranged spin correlations
• Topological Majorana flat bands in the Kitaev model on a Bishamon-kikko lattice
• Long-range spin correlations in a honeycomb spin model with magnetic field
• Quantum phase transitions in the Kitaev--Heisenberg model on a single hexagon
• Bond disorder in extended Heisenberg-Kitaev models: Spin textures and in-gap states in the high-field regime
• Temperature-dependent magnetic anisotropy from directional-dependent interactions