Abstract
The effective g-factor of 2D holes in modulation doped \mbox{p-SiGe/Ge/SiGe} structures was studied. The AC conductivity of samples with hole densities from 3.9 × 10¹¹~to 6.2 × 10¹¹ cm⁻² was measured in perpendicular magnetic fields up to 8 T using a contactless acoustic method. From the analysis of the temperature dependence of conductivity oscillations, the g_⊥-factor of each sample was determined. The g_⊥-factor was found to be decreasing approximately linearly with hole density. This effect is attributed to non-parabolicity of the valence band.