Possible observation of a spin-density wave inLa2CuO4by Raman scattering

Abstract

The multipeaked Raman spectrum in samples of ${\mathrm{La}}_2$ ${\mathrm{CuO}}_4$ in the region from ∼300 to ∼1420 ${\mathrm{cm}}^{\mathrm{-}1}$ is modeled. We report a striking example of such a spectrum from room temperature to ∼500 K in a single-crystal sample. An explanation of the spectrum is proposed based on the allowed excitation of spin-wave modes in the presence of a spin-density wave. The role of the dynamic spin-correlation length in broadening the spin-wave spectrum and in affecting the temperature and sample dependence of the spectrum is also discussed.