Spectroscopic ellipsometry study of optical anisotropy in Gd5Si2Ge2 and comparison with reflectance difference spectra

J. M. Park, Iowa State University
David W. Lynch, Iowa State University
S. J. Lee, Iowa State University
Deborah L. Schlagel Schlagel, Ames Laboratory, Iowa State University
Thomas A. Lograsso, Iowa State University
Alexandra O. Tsokol, Iowa State University
J. E. Snyder, Iowa State University
David C. Jiles, Cardiff University

This is an article from Physical Review B 73 (2006): 035110, doi: 10.1103/PhysRevB.73.035110. Posted with permission.

Abstract

The complex dielectric functions of single crystals of Gd5Si2Ge2 were obtained using spectroscopic ellipsometry (SE) in the photon energy range of 1.5–5.0eV at room temperature. Reflectance difference (RD) spectra for the a‐b and b‐c planes of single crystals of Gd5Si2Ge2 were derived from these dielectric functions and compared to those obtained from reflectance difference spectroscopy (RDS) at near-normal incidence. The two experimental RD spectra from SE and RDS agreed well. The in-plane optical anisotropy of the sample is mainly due to intrinsic bulk properties because of its larger magnitude (4×10−2) compared to surface-induced optical anisotropies, with a magnitude of only about 10−3 for a typical cubic material.