Temperature-dependent electron Lande g factor and the interband matrix element of GaAs

Very high precision measurements of the electron Lande g factor in GaAs are presented using spin-quantum beat spectroscopy at low excitation densities and temperatures ranging from 2.6 to 300 K. In colligation with available data for the temperature-dependent effective mass temperature dependence of the interband matrix element within a common five-level k center dot p theory can model both parameters consistently. A strong decrease in the interband matrix element with increasing temperature consistently closes a long lasting gap between experiment and theory and substantially improves the modeling of both parameters.