Piezo-optics of GaAs.

Abstract

We have obtained the three independent complex components ${\mathit{P}}_{11}$(\ensuremath{\omega}), ${\mathit{P}}_{12}$(\ensuremath{\omega}), and ${\mathit{P}}_{44}$(\ensuremath{\omega}) of the linear piezo-optical tensor ${\mathit{P}}_{\mathit{i}\mathit{j}\mathit{k}\mathit{l}}$(\ensuremath{\omega}) [\ensuremath{\Delta}${\mathrm{\ensuremath{\epsilon}}}_{\mathit{i}\mathit{j}}$(\ensuremath{\omega})=${\mathit{P}}_{\mathit{i}\mathit{j}\mathit{k}\mathit{l}}$(\ensuremath{\omega})${\mathit{X}}_{\mathit{k}\mathit{l}}$] of GaAs in the \ensuremath{\sim}1.5--5.4-eV photon-energy range (visible UV) by applying static uniaxial stress (X) along the high-symmetry directions [100] and [111] and measuring the stress-induced changes in the dielectric function \ensuremath{\epsilon}(\ensuremath{\omega}). These measurements were performed using a conventional rotating analyzer ellipsometer at room temperature. The measured components of the piezo-optical tensor are in agreement with prior Kramers-Kronig analysis of piezoreflectance data. Each component of ${\mathit{P}}_{\mathit{i}\mathit{j}\mathit{k}\mathit{l}}$(\ensuremath{\omega}) is also compared with band-structure-based calculations performed with the empirical pseudopotential method. The calculations are in reasonable agreement with the experiment. Improved deformation-potential constants ${\mathit{D}}_{1}^{1}$, ${\mathit{D}}_{1}^{5}$, ${\mathit{D}}_{3}^{3}$, and ${\mathit{D}}_{3}^{5}$ for the ${\mathit{E}}_{1}$-${\mathit{E}}_{1}$+${\mathrm{\ensuremath{\Delta}}}_{1}$ transitions were also obtained from an analysis of the ellipsometric data. They compare favorably with theoretical estimates. In particular, the experimental value of ${\mathit{D}}_{3}^{5}$ agrees rather well with band-structure-based calculations, in contrast with previous measurements of this parameter.