Theoretical analysis of magnetic Raman scattering in La2CuO4: Two-magnon intensity with the inclusion of ring exchange

Article

关键词: CYCLIC 4-SPIN EXCHANGE;    HIGH-ENERGY SPIN;    T-J MODEL;    ANTIFERROMAGNETIC INSULATORS;    HEISENBERG-ANTIFERROMAGNET;    SQUARE LATTICE;    HUBBARD-MODEL;    EXCITATIONS;    TEMPERATURE;    SPECTRUM;   

DOI  :  10.1103/PhysRevB.67.100404

来源: SCIE

【 摘 要 】

We evaluate the Raman light-scattering intensity for the square lattice Heisenberg antiferromagnet with plaquette ring exchange J(square). With the exchange couplings as fixed before from an accurate fit to the spin-wave dispersion in La2CuO4, leading in particular to J(square)=0.24J, we demonstrate in a parameter-free calculation that the inclusion of the plaquette exchange contribution to the dispersion and the magnon-magnon interaction vertex gives a peak position in B-1g scattering geometry E-max=2.71J which is in excellent agreement with the experimental data. Yet, the intrinsic width and the line shape of the two-magnon remain beyond a description in terms of a spin-only Hamiltonian.

【 授权许可】

Free