Raman scattering study of multimagnon (bi- and tri-magnon) excitations and rotonlike points in the distorted triangular lattice antiferromagnet
arXiv:2302.06642 · doi:10.1103/PhysRevB.107.184402
Abstract
We investigate the experimental signatures of Raman spectroscopy of bi- and tri-magnon excitations in the distorted triangular lattice antiferromagnets alpha-LCr2O4 (L=Sr, Ca). We utilize spin wave theory to analyze the nearly 120 degree spin-3/2 spiral ordered antiferromagnetic ground state to compute the single-magnon density of states, single-magnon dispersion, and bimagnon and trimagnon Raman spectra (polarized and unpolarized). It is found that Raman scattering is capable of capturing the effect of the rotonlike M and M' points on the bimagnon Raman spectrum. Our calculation confirms the connection between single-magnon rotonlike excitation energy and bimagnon Raman excitation spectrum observed experimentally. The roton energy minimum in momentum space is half of the energy of a bimagnon excitation signal. The experimental magnetic Raman scattering result displays two peaks which have a Raman shift of 15 meV and 40 meV, respectively. Theoretical modeling and analysis of the experimental spectrum of alpha-SrCr2O4 within our distorted Heisenberg Hamiltonian lattice suggests that the low-energy peak at 15 meV is associated with the bimagnon excitation, whereas the high-energy peak around 40 meV is primarily a trimagnon excitation. Based on our fitting procedure we propose a new set of magnetic interaction parameters for alpha-SrCr2O4. These parameters reproduce not only the experimental Raman spectrum, but also the inelastic neutron scattering response (including capturing high energy magnon branches). We also compute the unpolarized bimagnon and trimagnon Raman spectra for alpha-CaCr2O4. Furhtermore, we found that the polarization sensitivity of Raman spectrum can be utilized to distinguish the bi- and tri-magnon excitation channels.
arXiv comment11 pages, 4 figures
References in corpus (38)
- Exact spectra, spin susceptibilities and order parameter of the quantum Heisenberg antiferromagnet on the triangular lattice
- Experimental Realization of Spin-1/2 Triangular-Lattice Heisenberg Antiferromagnet
- Observation of extended scattering continua characteristic of spin fractionalization in the 2D frustrated quantum magnet Cs2CuCl4 by neutron scattering
- Unusual ordered phases of highly frustrated magnets: a review
- Spin-waves in triangular lattice antiferromagnet: decays, spectrum renormalization, and singularities
- Magnetization Process and Collective Excitations in the S=1/2 Triangular-Lattice Heisenberg Antiferromagnet Ba3CoSb2O9
- Quantum Phase Diagram of the Triangular-Lattice XXZ Model in a Magnetic Field
- Phase diagram for a class of spin-half Heisenberg models interpolating between the square-lattice, the triangular-lattice and the linear chain limits
- Excitation spectra of the spin-1/2 triangular-lattice Heisenberg antiferromagnet
- Dynamical structure factor of triangular-lattice antiferromagnet
- Anomalous Excitation Spectra of Frustrated Quantum Antiferromagnets
- Flat spin wave dispersion in a triangular antiferromagnet
- Spin dynamics in the geometrically frustrated multiferroic CuCrO2
- Microscopic Model Calculations for the Magnetization Process of Layered Triangular-Lattice Quantum Antiferromagnets
- Quantum phase diagram of the triangular-lattice antiferromagnet BaCoSbO
- Quasiclassical magnetic order and its loss in a spin-1/2 Heisenberg antiferromagnet on a triangular lattice with competing bonds
- Successive phase transitions and phase diagrams of the quasi-two-dimensional triangular antiferromagnet Rb4Mn(MoO4)3
- Magnons and Excitation Continuum in XXZ triangular antiferromagnetic model: Application to
- Variational wave functions for the Heisenberg model on the anisotropic triangular lattice: Spin liquids and spiral orders
- Phases of triangular lattice antiferromagnet near saturation
- Modified spin-wave theory with ordering vector optimization II: Spatially anisotropic triangular lattice and model with Heisenberg interactions
- Excitation spectra and ground state properties of the layered spin-1/2 frustrated antiferromagnets Cs_2CuCl_4 and Cs_2CuBr_4
- Raman scattering in a Heisenberg {\boldmath } antiferromagnet on the triangular lattice
- Non-Collinear Magnetic Phases of a Triangular-Lattice Antiferromagnet and Doped CuFeO
- Helical magnetic state in the distorted triangular lattice of alpha-CaCr2O4
- Magnetic soft modes in the locally distorted triangular antiferromagnet alpha-CaCr2O4
- 120° Helical Magnetic Order in the Distorted Triangular Antiferromagnet alpha-CaCr2O4
- Raman scattering for triangular lattices spin-1/2 Heisenberg antiferromagnets
- Helical magnetism and structural anomalies in triangular lattice α-SrCr2O4
- Raman scattering in a Heisenberg S=1/2 antiferromagnet on the anisotropic triangular lattice
- Critical Anisotropies of a Geometrically-Frustrated Triangular-Lattice Antiferromagnet
- Signatures of indirect K-edge resonant inelastic x-ray scattering on magnetic excitations in triangular lattice antiferromagnet
- Raman study of magnetic excitations and magneto-elastic coupling in alpha-SrCr2O4
- Spin Casimir Effect in Non-collinear Quantum Antiferromagnets
- Softened magnetic excitations in the s = 3/2 distorted triangular antiferromagnet alpha-CaCr2O4
- Magnetic excitations in quasi-one dimensional helimagnets: Magnon decays and in uence of the inter-chain interactions
- 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
- Torque equilibrium spin wave theory of Raman scattering in an anisotropic triangular lattice antiferromagnet with Dzyaloshinskii-Moriya interaction