Nonlinear optical properties of perovskite YMnO3 studied by real-space recursion method
Abstract
New types of second-order nonlinear optical properties of hexagonal YMnO3 have been studied, caused by the coexistence of the noncentrosymmetric ferroelectric ordering of charges and the centrosymmetric spin ordering below its Neel temperature TN. Using time-dependent perturbation theory and the Green's function method, we have derived an expression for the nonlinear optical susceptibility in terms of the real-space Green's function. Then, based upon the multiband Hubbard Hamiltonian and the unrestricted Hartree-Fock approximation, the real-space recursion method has been used to calculate the electric structure of YMnO3 below TN, and its nonlinear optical susceptibility. The calculated results are very consistent with the experimental observation, and clearly show different contributions to the nonlinear optical response from the Mn eg and Op bands in YMnO3.
- Publication:
-
Physical Review B
- Pub Date:
- April 2000
- DOI:
- 10.1103/PhysRevB.61.10664
- Bibcode:
- 2000PhRvB..6110664W
- Keywords:
-
- 77.80.-e;
- 71.15.-m;
- Ferroelectricity and antiferroelectricity;
- Methods of electronic structure calculations