Resonant two-magnon raman scattering in cuprate antiferromagnetic insulators

초록

We present results of low-temperature two-magnon resonance Raman excitation profile measurements for single-layer Sr 2 Cu O 2 Cl 2 and bilayer Y Ba 2 Cu 3 O 6 + δ antiferromagnets over the excitation region from 1.65 to 3.05 eV. These data reveal composite structure of the two-magnon line shape and strong nonmonotic dependence of the scattering intensity on excitation energy. We analyze these data using the triple resonance theory of Chubukov and Frenkel [Phys. Rev. Lett. 74, 3057 (1995)] and deduce information about magnetic interaction and band parameters in these materials.