Spin–orbit parameters derivation using single-frequency analysis of InGaAs multiple quantum wells in transient spin dynamics regime

The deriving method of spin–orbit (SO) parameters using a single-frequency analysis was examined in a transient regime of diffusive spin dynamics in InGaAs/InAlAs multiple quantum wells. Transient regime of diffusive spin dynamics is the time regime when the spin precession frequency induced by SO magnetic fields decreases and changes with time. Recently, we have established a method of deriving SO parameters by scanning time-resolved Kerr rotation microscopy in this transient regime [Kawaguchi et al., Appl. Phys. Lett. 115, 172406 (2019)] using the time-dependent spin precession frequency analysis. Although reliable SO parameters were derived, time-independent single-frequency analysis is still attractive because of its simplicity. In this paper, SO parameters’ derivation was performed by the single-frequency analysis comparing the experiment and the Monte Carlo (MC) simulation. The best fit of the simulation to the measurement for the SO-induced frequency yields the derivation of SO parameters; however, the derived values were different from the reliable SO parameters derived by the time-dependent analysis. This discrepancy arises from a spin relaxation time difference between the experiment and MC simulation. After intentionally adjusting the spin relaxation time of the MC simulation to the experiment, the SO-induced frequency obtained by the MC simulation with reliable SO parameters reproduced the experiment well. We found that the spin relaxation time adjustment of the MC simulation to the experiment is necessary to obtain accurate SO parameters from the single-frequency analysis comparing the experiment with the MC simulation.