Split-Off Valence-Band Parameters for GaAs from Stress-Modulated Magnetoreflectivity

We have measured the spin-orbit split-off valence-band parameters in high-purity epitaxial GaAs at ∼ 30°K by means of stress-modulated interband magnetoreflectivity. Our results are $(\frac{m}{m_c}-\frac{m}{m_{\mathrm{so}}})=21.\mathrm{}5\pm 0.4$, $g_c+g_{\mathrm{so}}=-4.\mathrm{}7\pm 1.0$, where $m_c$ and $m_{\mathrm{so}}$ are the conduction-band and split-off-band effective masses and $g_c$ and $g_{\mathrm{so}}$ are the corresponding effective $g$ factors. From these results, we deduce $\frac{m_{\mathrm{so}}}{m}=-0.\mathrm{}154\pm 0.010$, $g_{\mathrm{so}}=-4.\mathrm{}9\pm 1.0$, and ${\kappa }^L=1.\mathrm{}2\pm 0.25$, where ${\kappa }^L$ is related to the antisymmetric constant introduced by Luttinger.