Control of electron-spin coherence using Landau level quantization in a two-dimensional electron gas

Time-resolved optical measurements of electron-spin dynamics in modulation-doped InGaAs quantum wells are used to explore electron spin coherence times and spin precession frequencies in a regime where an out-of-plane magnetic field quantizes the states of a two-dimensional electron gas into Landau levels. Oscillatory features in the transverse spin coherence time and effective g factor as a function of the applied magnetic field exhibit a correspondence with Shubnikov–de Haas oscillations, illustrating a coupling between spin and orbital eigenstates. We present a theoretical model in which inhomogeneous dephasing due to the population of different Landau levels limits the spin coherence time and captures the essential experimental results.