Study of transport, phase, and spin relaxation times of 2D electrons by means of pressure

We report magnetoconductivity experiments carried out on pseudomorphic AlGaAs/InGaAs/GaAs quantum wells in a wide range of magnetic fields (0.1 to 80 kG). Pressure-illumination cycles were used for tuning the free electron density. Measurements of the Shubnikov-de Haas and Hall effects allowed us to determine the transport and quantum relaxation times. Corrections to the magnetoconductivity due to weak localization and weak antilocalization were determined and used to calculate the phase and spin relaxation times. We analyzed phase, spin, quantum, and transport relaxation rates as a function of electron density which allowed for a characterization of the dominant scattering processes.