Microscopic Mechanism of Raman Scattering in EuTe

Abstract

The dependence of the line shapes on the excitation energy in the Raman scattering (RS) of EuTe at low temperatures is theoretically studied, and is interpreted in terms of the modulation of 5d spin-orbit interaction by lattice displacement. A sharp line induced by the staggered magnetization appears in the vicinity of the absorption edge. This line is observed in off-diagonal Raman polarization configuration. For the incident light with energy near the middle of the exciton absorption, the sharp line disappears and broad line assisted by the magnon excitation appears in both off-diagonal and diagonal polarization configurations. These calculated results are consistent with the experimental result. The RS spectra under a weak magnetic field are also calculated.