Piezo-optics of GaAs

We have obtained the three independent complex components ${\mathit{P}}_{11}$(ω), ${\mathit{P}}_{12}$(ω), and ${\mathit{P}}_{44}$(ω) of the linear piezo-optical tensor ${\mathit{P}}_{\mathit{i}\mathit{j}\mathit{k}\mathit{l}}$(ω) [Δ${\mathrm{\epsilon }}_{\mathit{i}\mathit{j}}$(ω)=${\mathit{P}}_{\mathit{i}\mathit{j}\mathit{k}\mathit{l}}$(ω)${\mathit{X}}_{\mathit{k}\mathit{l}}$] of GaAs in the ∼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 ε(ω). 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 ${\mathit{P}}_{\mathit{i}\mathit{j}\mathit{k}\mathit{l}}$(ω) 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 ${\mathit{E}}_1$-${\mathit{E}}_1$+${\mathrm{\Delta }}_1$ 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.