Excitation spectra of the spin-1/2 triangular-lattice Heisenberg antiferromagnet

Abstract

We use series expansion methods to calculate the dispersion relation of the one-magnon excitations for the spin-1/2 triangular-lattice nearest-neighbor Heisenberg antiferromagnet above a three-sublattice ordered ground state. Several striking features are observed compared to the classical (large-S) spin-wave spectra. Whereas at low energies the dispersion is only weakly renormalized by quantum fluctuations, significant anomalies are observed at high energies. In particular, we find roton-like minima at special wave-vectors and strong downward renormalization in large parts of the Brillouin zone, leading to very flat or dispersionless modes. We present detailed comparison of our calculated excitation energies in the Brillouin zone with the spin-wave dispersion to order 1/S calculated recently by Starykh, Chubukov, and Abanov [cond-mat/0608002]. We find many common features but also some quantitative and qualitative differences. We show that at temperatures as low as 0.1J the thermally excited rotons make a significant contribution to the entropy. Consequently, unlike for the square lattice model, a non-linear sigma model description of the finite-temperature properties is only applicable at extremely low temperatures.

14 pages, 11 figures

References in corpus (7)

• U(1) Gauge Theory of the Hubbard Model : Spin Liquid States and Possible Application to k-(BEDT-TTF)_2 Cu_2 (CN)_3
• Emergence of inhomogeneous moments from spin liquid in the triangular-lattice Mott insulator $\kappa$-(ET)${}_2$Cu${}_2$(CN)${}_3$
• Magnon Decay in Noncollinear Quantum Antiferromagnets
• Flat spin wave dispersion in a triangular antiferromagnet
• Magnetism and superconductivity of strongly correlated electrons on the triangular lattice
• Spin dynamics of the quasi two dimensional spin-1/2 quantum magnet Cs_2CuCl_4
• Spin Structure Factor of the Frustrated Quantum Magnet Cs_2CuCl_4

Cited by in corpus (68)

• Quantum frustration in organic Mott insulators: from spin liquids to unconventional superconductors
• Spontaneous Magnon Decays
• Spin liquid phase of the $S=\frac{1}{2}$ $J_1-J_2$ Heisenberg model on the triangular lattice
• Unusual ordered phases of highly frustrated magnets: a review
• Mott insulating states with competing orders in the triangular lattice Hubbard model
• Numerical Linked-Cluster Algorithms. I. Spin systems on square, triangular, and kagome lattices
• Frustrated two dimensional quantum magnets
• Witnessing quantum criticality and entanglement in the triangular antiferromagnet KYbSe${}_2$
• The phase diagram of the antiferromagnetic XXZ model on the triangular lattice
• Quasiclassical magnetic order and its loss in a spin-1/2 Heisenberg antiferromagnet on a triangular lattice with competing bonds
• Bold Diagrammatic Monte Carlo Method Applied to Fermionized Frustrated Spins
• Algebraic vortex liquid theory of a quantum antiferromagnet on the kagome lattice
• Riemannian optimization of isometric tensor networks
• Topological Magnetoelastic Excitations in Non-Collinear Antiferromagnets
• Ba8CoNb6O24: a spin-1/2 triangular-lattice Heisenberg antiferromagnet in the 2D limit
• Avoided quasiparticle decay and enhanced excitation continuum in the spin-1/2 near-Heisenberg triangular antiferromagnet Ba3CoSb2O9
• Magnons and Excitation Continuum in XXZ triangular antiferromagnetic model: Application to $B{a}_{3}CoS{b}_2{O}_9$
• Spin Excitation Spectra of Anisotropic Spin-$1/2$ Triangular Lattice Heisenberg Antiferromagnets
• Bold Diagrammatic Monte Carlo technique for frustrated spin systems
• Thermodynamics of the Up-Up-Down Phase of the S = 1/2 Triangular-Lattice Antiferromagnet Cs${}_2$CuBr${}_4$
• Spectral function of the $J_1-J_2$ Heisenberg model on the triangular lattice
• Modified spin-wave theory with ordering vector optimization II: Spatially anisotropic triangular lattice and $J_1{J}_2{J}_3$ model with Heisenberg interactions
• Dynamical Signatures of Symmetry Broken and Liquid Phases in an $S=1/2$ Heisenberg Antiferromagnet on the Triangular Lattice
• Magnetic order in coupled spin-half and spin-one Heisenberg chains in anisotropic triangular-lattice geometry
• Raman scattering in a Heisenberg {\boldmath $S=1/2$} antiferromagnet on the triangular lattice
• Excitation spectra and ground state properties of the layered spin-1/2 frustrated antiferromagnets Cs_2CuCl_4 and Cs_2CuBr_4
• Field-induced decays in $XXZ$ triangular-lattice antiferromagnets
• Revealing the Phase Diagram of Kitaev Materials by Machine Learning: Cooperation and Competition between Spin Liquids
• Numerical study of incommensurability of the spiral state on spin-1/2 spatially anisotropic triangular antiferromagnets using entanglement renormalization
• Low temperature properties of the triangular-lattice antiferromagnet: a bosonic spinon theory
• Real-space perturbation theory for frustrated magnets: application to magnetization plateaus
• Quantum fluctuations in anisotropic triangular lattices with ferro- and antiferromagnetic exchange
• Double Magnon-Roton Excitations in the Triangular-Lattice Spin Supersolid
• Theory of the anomalous spin dynamics of spin-$\frac{1}{2}$ triangular lattice Heisenberg antiferromagnet and its application to Ba${}_3$CoSb${}_2$O${}_9$
• Magnetization of the spin-1/2 Heisenberg antiferromagnet on the triangular lattice
• Holes and magnetic polarons in a triangular lattice antiferromagnet
• Ground-state and thermodynamic properties of the spin-$\frac{1}{2}$ Heisenberg model on the anisotropic triangular lattice
• Quantum magnetisms in uniform triangular lattices Li2AMo3O8 (A = In, Sc)
• Structures of magnetic excitations in the spin-1/2 kagome-lattice antiferromagnets Cs${}_2$Cu${}_3$SnF${}_{12}$ and Rb${}_2$Cu${}_3$SnF${}_{12}$
• Signatures of indirect K-edge resonant inelastic x-ray scattering on magnetic excitations in triangular lattice antiferromagnet
• Phase diagrams and excitations of anisotropic $S=1$ quantum magnets on the triangular lattice
• Simulating Spin Dynamics of Supersolid States in a Quantum Ising Magnet
• Novel elementary excitations in spin-1/2 antiferromagnets on the triangular lattice
• Softened magnetic excitations in the s = 3/2 distorted triangular antiferromagnet alpha-CaCr2O4
• Magnons and Spinons in ${\mathrm{Ba}}_2{\mathrm{CoTeO}}_6$: A Composite System of Isolated Spin-$1/2$ Triangular Heisenberg-like and Frustrated Honeycomb Ising-like Antiferromagnets
• Collective excitations in two-dimensional antiferromagnet in strong magnetic field
• Possible coexistence of short-range resonating-valence-bond and long-range stripe correlations in the spatially anisotropic triangular-lattice quantum magnet Cu${}_2$(OH)${}_3$NO${}_3$
• Easy-axis Heisenberg model on the triangular lattice: from supersolid to gapped solid
• Non-perturbative linked-cluster expansions in long-range ordered quantum systems
• On the Magnetization of the $120^{\circ }$ order of the Spin-1/2 Triangular Lattice Heisenberg Model: a DMRG revisit
• Why the Schwinger Boson mean field theory fails to describe the spin dynamics of the triangular lattice antiferromagnetic Heisenberg model?
• Torque equilibrium spin wave theory of Raman scattering in an anisotropic triangular lattice antiferromagnet with Dzyaloshinskii-Moriya interaction
• Modified large-$N$ approach to gapless spin liquids, magnetic orders, and dynamics: Application to triangular lattice antiferromagnets
• Dynamics of spin-1/2 $J_1$-$J_2$ model on the triangular lattice
• Thermal features of Heisenberg antiferromagnets on edge- versus corner-sharing triangular-based lattices: A message from spin waves
• Interacting triplons in frustrated spin ladders: Binding and decay in BiCu${}_2$PO${}_6$
• A Series Expansion Study for Large Negative Quantum Renormalization of Magnon Spectra in the $S=1/2$ Kagome-Lattice Heisenberg Antiferromagnet Cs${}_2$Cu${}_3$SnF${}_{12}$
• Raman scattering study of multimagnon (bi- and tri-magnon) excitations and rotonlike points in the distorted triangular lattice antiferromagnet
• Inverse Hamiltonian design of highly-entangled quantum systems
• Topical review: the nature of the ground state and possibility of a quantum spin liquid in 1T metal dichalcogenides
• Variational optimization of projected entangled-pair states on the triangular lattice
• Non-linear spin wave theory in the strong easy-axis limit of the triangular XXZ model
• Nontrivial three-sublattice magnetization in the easy-axis spin-1/2 XXZ antiferromagnet on the triangular lattice
• Magnon Spectrum of the Amorphous Ferromagnet Co${}_4$P from Atomistic Spin Dynamics
• An integrated theoretical and numerical approach to understand modern experiments on quantum magnetism
• Quantum spin liquid ground state with the evidence of roton-like excitations at elevated temperatures in the triangular-lattice delafossite YbCuSe${}_2$
• Specific heat and susceptibility of S=1/2 antiferromagnets on square, triangular, and kagome lattices
• Competing states in the $S=1/2$ triangular-lattice $J_1$-$J_2$ Heisenberg model: a dynamical density-matrix renormalization group study