Magnetic field effects on the Kitaev model coupled to environment

Abstract

Open quantum systems display unusual phenomena not seen in closed systems, such as new topological phases and unconventional phase transitions. An interesting example was studied for a quantum spin liquid in the Kitaev model [K. Yang, S. C. Morampudi, and E. J. Bergholtz, Phys. Rev. Lett. $126$, 077201 (2021)]; an effective non-Hermitian Kitaev model, which incorporates dissipation effects, was shown to give rise to a gapless spin liquid state with exceptional points in the Majorana dispersions. Given that an external magnetic field induces a gapped Majorana topological state in the Hermitian case, the exceptional points may bring about intriguing quantum phenomena under a magnetic field. Here we investigate the non-Hermitian Kitaev model perturbed by the magnetic field. We show that the exceptional points remain gapless up to a finite critical magnetic field, in stark contrast to the Hermitian case where an infinitesimal field opens a gap. The gapless state is stable over a wide range of the magnetic field for some particular parameter sets, and in special cases, undergoes topological transitions to another gapless state with different winding number around the exceptional points without opening a gap. In addition, in the system with edges, we find that the non-Hermitian skin effect is induced by the magnetic field, even for the parameters where the skin effect is absent at zero field. The chirality of edge states is switched through the exceptional points, similarly to the surface Fermi arcs connected by the Weyl points in three-dimensional Weyl semimetals. Our results provide a new possible route to stabilize topological gapless quantum spin liquids under the magnetic field in the presence of dissipation.

16 pages, 10 figures

References in corpus (41)

• Non-Abelian Anyons and Topological Quantum Computation
• Mott Insulators in the Strong Spin-Orbit Coupling Limit: From Heisenberg to a Quantum Compass and Kitaev Models
• Non-Hermitian Physics
• Quantum trajectories and open many-body quantum systems
• $\alpha$-RuCl3: a Spin-Orbit Assisted Mott Insulator on a Honeycomb Lattice
• Edge Modes, Degeneracies, and Topological Numbers in Non-Hermitian Systems
• Models and Materials for Generalized Kitaev Magnetism
• Non-Hermitian Topology and Exceptional-Point Geometries
• On the Origin of Zigzag Magnetic Order in Iridium Oxide Na2IrO3
• Exact results for spin dynamics and fractionization in the Kitaev Model
• Non-Hermitian topological phenomena: A review
• Successive magnetic phase transitions in $\mathbf{\alpha }$-RuCl${}_3$: XY-like frustrated magnet on the honeycomb lattice
• Topological Non-Hermitian skin effect
• Pseudospin exchange interactions in d^7 cobalt compounds: Possible realization of the Kitaev model
• Na2IrO3 as a spin-orbit-assisted antiferromagnetic insulator with a 340 meV gap
• Kitaev-Heisenberg Hamiltonian for High-Spin $d^7$ Mott Insulators
• Kitaev Spin Liquid in 3d Transition Metal Compounds
• Symmetry-protected multifold exceptional points and their topological characterization
• Dissipative Dynamics and Phase Transitions in Fermionic Systems
• Topological phases in ultracold polar-molecule quantum magnets
• Electronic Structure of the Kitaev Material $\alpha$-${\text{RuCl}}_3$ Probed by Photoemission and Inverse Photoemission Spectroscopies
• Exceptional Spin Liquids from Couplings to the Environment
• Non-Hermitian Topological Phases: Principles and Prospects
• Engineering and probing non-Abelian chiral spin liquids using periodically driven ultracold atoms
• Non-Abelian Floquet Spin Liquids in a Digital Rydberg Simulator
• Implementation of Clifford gates in the Ising-anyon topological quantum computer
• Spin-orbital entangled state and realization of Kitaev physics in 3d cobalt compounds: a progress report
• Impact of off-diagonal exchange interactions on the Kitaev spin liquid state of $\alpha$-RuCl${}_3$
• Non-Hermitian band topology with generalized inversion symmetry
• Hermitian Bulk -- Non-Hermitian Boundary Correspondence
• Collective excitations in the tetravalent lanthanide honeycomb antiferromagnet, Na2PrO3
• Strong antiferromagnetic interaction owing to a large trigonal distortion in the spin-orbit-coupled honeycomb lattice iridate CdIrO${}_3$
• Enhanced eigenvector sensitivity and algebraic classification of sublattice-symmetric exceptional points
• Electronic and magnetic properties of iridium ilmenites $A$IrO${}_3$ ($A=$ Mg, Zn, and Mn)
• Magnetoelectric generation of a Majorana-Fermi surface in Kitaev's honeycomb model
• Exceptional dynamics of interacting spin liquids
• An exactly solvable dissipative spin liquid
• Topological Nematic Phase Transition in Kitaev Magnets Under Applied Magnetic Fields
• Feasibility of Kitaev quantum spin liquids in ultracold polar molecules
• Asymmetric modulation of Majorana excitation spectra and nonreciprocal thermal transport in the Kitaev spin liquid under a staggered magnetic field
• Discriminant indicators with generalized inversion symmetry