Magnons and excitation continuum in XXZ triangular antiferromagnetic model: Application toBa3CoSb2O9

2014/11/30 by E. A. Ghioldi, Alejandro Mezio, A. Mezio +5 · 7 citations
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Anisotropy #Antiferromagnetism #Boson #Condensed matter physics #Excitation #Geology #Lattice (music) #Magnetic and transport properties of perovskites and related materials #Magnon #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Series (stratigraphy) #Spectral line #Spinon #cond-mat.str-el

paper · pdf · doi:10.1103/physrevb.91.134423

published as Published in Phys. Rev. B, 134423 (2015) · 8 pages, 4 figures

openalex publication_date 2015/04/22 · arxiv created 2015/04/23 · arxiv updated 2015/04/24 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06

Abstract

We investigate the excitation spectrum of the triangular-lattice antiferromagnetic XXZ model using series expansion and mean field Schwinger boson approaches. The single-magnon spectrum computed with series expansion exhibits rotonic minima at the middle points of the edges of the Brillouin zone, for all values of the anisotropy parameter in the range 0\ensuremath≤J^z/J\ensuremath≤1. Based on the good agreement with series expansion for the single-magnon spectrum, we compute the full dynamical magnetic structure factor within the mean field Schwinger boson approach to investigate the relevance of the XXZ model for the description of the unusual spectrum found recently in Ba₃CoSb₂O₉. In particular, we obtain an extended continuum above the spin wave excitations, which is further enhanced and brought closer to those observed in Ba₃CoSb₂O₉ with the addition of a second neighbor exchange interaction approximately 15% of the nearest-neighbor value. Our results support the idea that excitation continuum with substantial spectral-weight are generically present in two-dimensional frustrated spin systems and fractionalization in terms of bosonic spinons presents an efficient way to describe them.

Citations

• On the ground state properties of the anisotropic triangular antiferromagnet
• Experimental Realization of a 2D Fractional Quantum Spin Liquid
• Large-Nexpansion for frustrated quantum antiferromagnets
• Theory of the algebraic vortex liquid in an anisotropic spin-12triangular antiferromagnet
• Deconfined Quantum Critical Points
• Quantum orders and symmetric spin liquids

Cited by

• Torque equilibrium spin wave theory study of anisotropy and Dzyaloshinskii-Moriya interaction effects on the indirect K-edge RIXS spectrum of a triangular lattice antiferromagnet
• Resonating valence bond theory of anomalous spin dynamics of spin-12 triangular lattice Heisenberg antiferromagnet and its application to Ba3CoSb2O9
• Chern-Simons fermionization approach to two-dimensional quantum magnets: Implications for antiferromagnetic magnons and unconventional quantum phase transitions
• Multimagnon and multispinon L₃-edge RIXS spectra of an effective J₁-J₂-J₃ square lattice Heisenberg model
• Hybridization and Decay of Magnetic Excitations in Two-Dimensional Triangular Lattice Antiferromagnets
• Avoided quasiparticle decay and enhanced excitation continuum in the spin-12 near-Heisenberg triangular antiferromagnet Ba3CoSb2O9
• Dynamical structure factor of the triangular antiferromagnet: Schwinger boson theory beyond mean field