Dielectric function decomposition by dipole interaction distribution: application to triclinic K2Cr2O7

Abstract

Here we present a general approach for the description for the frequency dependent dielectric tensor coefficients for optically anisotropic materials. Based on symmetry arguments we show that the components of the dielectric tensor are in general not independent of each other. For each excitation there exists an eigensystem, where its contribution to the dielectric tensor can be described by a diagonal susceptibility tensor. From the orientation of the eigensystem and the relative magnitude of the tensor elements, the dipole interaction distribution in real space can be deduced. In the limiting cases, the oriented dipole approach as well as the tensor of isotropic and uniaxial materials are obtained. The application of this model is demonstrated exemplarily on triclinic K _2 Cr _2 O _7 and the orientation and directional distribution of the corresponding dipole moments in real space are determined.

Keywords

• ellipsometry
• dielectric function
• optical anisotropy