Weak localization in high-quality two-dimensional systems

We investigate five different methods of modeling the correction to the magnetoconductivity due to the weak localization effect in two-dimensional (2D) systems. The phase breaking rate is extracted using each method by fitting experimental magnetoconductivity data of high-quality 2D GaAs hole systems over the range of carrier densities and temperatures that weak localization is observed. We find that despite corrections to the magnetoconductivity differing by more than 100% between different methods valid beyond the diffusion approximation, the phase breaking rate extracted is approximately the same. We also find that if diffusive transport is incorrectly assumed in high-quality systems, then values of the phase breaking rate approximately 2.5 times too high are extracted. We demonstrate the regime in which the diffusive transport approximation holds and explain previous discrepancies in the literature where phase breaking rates much higher than expected from Fermi-liquid theory have been obtained. We find good agreement of the phase breaking rate with Fermi-liquid theory until k_Fl begins to approach 1.