The temperature dependence of the electron spin g factor in GaAs is investigated experimentally and theoretically. Experimentally, the g factor was measured using time-resolved Faraday rotation due to Larmor precession of electron spins in the temperature range between 4.5 K and 190 K. The experiment shows an almost linear increase of the g value with the temperature. This result is in good agreement with other measurements based on photoluminescence quantum beats and time-resolved Kerr rotation up to room temperature. The experimental data are described theoretically taking into account a diminishing fundamental energy gap in GaAs due to lattice thermal dilatation and nonparabolicity of the conduction band calculated using a five-level kp model. At higher temperatures electrons populate higher Landau levels and the average g factor is obtained from a summation over many levels. A very good description of the experimental data is obtained indicating that the observed increase of the spin g factor with the temperature is predominantly due to band's nonparabolicity.
@article{arxiv.0809.2456,
title = {Temperature dependence of the electron spin g factor in GaAs},
author = {W. Zawadzki and P. Pfeffer and R. Bratschitsch and Z. Chen and S. T. Cundiff and B. N. Murdin and C. R. Pidgeon},
journal= {arXiv preprint arXiv:0809.2456},
year = {2009}
}