Abstract
We present a microscopic model to understand the magnetoelectric and second-harmonic spectra of and the interference effect between the magnetic and electric second-order optical polarizations. The spin-orbit interaction and the crystalline fields of correct symmetry around the ion, i.e., the axial and twisted crystalline field of symmetry, are treated as perturbation on the trigonal states of the system of . By these treatments we attempt to describe the observed phenomena associated with the transitions between and states in . It is possible to reproduce the observed spectra of the polarization rotation and ellipticity, and the second-harmonic generation spectra described by the nonlinear susceptibilities and . The estimated theoretical magnitudes of these quantities are in reasonable agreement with the observed magnitudes.
- Received 9 April 1997
DOI:https://doi.org/10.1103/PhysRevB.57.9586
©1998 American Physical Society