Abstract
The temperature dependence of the electron spin factor in GaAs is investigated experimentally and theoretically. Experimentally, the factor was measured using time-resolved Faraday rotation due to Larmor precession of electron spins in the temperature range between 4.5 and 190 K. The experiment shows an almost linear increase in the 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 model. According to the model, the factor increases when the electron energy increases in the band with the growing Landau level and the wave vector . At higher temperatures electrons populate higher Landau levels and the average factor is obtained from a summation over many levels and an integration over . A very good description of the experimental data is obtained indicating that the observed increase in the spin factor with the temperature is predominantly due to band’s nonparabolicity.
- Received 10 September 2008
DOI:https://doi.org/10.1103/PhysRevB.78.245203
©2008 American Physical Society