Symmetry analysis of theE2structures in Si by low-field electroreflectance

The precise analysis of the ${E}_{2}$ transitions in Si is described. From the line-shape analysis using the low-field resonant function, we show that the ${E}_{2}$ structures consist of three critical points, ${E}_{2}(1)$, ${E}_{2}(2)$, and ${E}_{2}(3)$, of type ${M}_{1}$, ${M}_{1}$, and ${M}_{2}$, respectively. The symmetry (and the reduced-mass relation) of the critical points are determined from the polarization anisotropies and the line shapes of low-field electroreflectance spectra: The ${E}_{2}(1)$ critical point is assigned conclusively to the ${\ensuremath{\Sigma}}_{2}^{\ensuremath{\nu}}\ensuremath{\rightarrow}{\ensuremath{\Sigma}}_{3}^{c}$ transition ($\frac{1}{{\ensuremath{\mu}}_{T2}}+\frac{1}{{\ensuremath{\mu}}_{L}}=\frac{4}{{\ensuremath{\mu}}_{T1}}$, ${\ensuremath{\mu}}_{T1}g0$, and ${\ensuremath{\mu}}_{T2}{\ensuremath{\mu}}_{L}l0$) and the ${E}_{2}(3)$ critical point is probably to the ${\ensuremath{\Delta}}_{5}^{\ensuremath{\nu}}\ensuremath{\rightarrow}{\ensuremath{\Delta}}_{1}^{c}$ transition near the $X$ point (${\ensuremath{\mu}}_{L}\ensuremath{\ll}|{\ensuremath{\mu}}_{T}|$, ${\ensuremath{\mu}}_{T}l0$, ${\ensuremath{\mu}}_{L}g0$).