Electron spin relaxation in GaAs1−xBix: Effects of spin-orbit tuning by Bi incorporation

The electron spin relaxation in n-type and intrinsic GaAs1−xBix with Bi composition 0≤x≤0.1 is investigated from the microscopic kinetic spin Bloch equation approach. The incorporation of Bi is shown to markedly decrease the spin relaxation time as a consequence of the modification of the spin-orbit interaction, which shows the feasibility of GaAs1−xBix in the applications of spintronic devices. We demonstrate that the density and temperature dependences of spin relaxation time in GaAs1−xBix resemble the ones in GaAs. Meanwhile, the Bir-Aronov-Pikus mechanism is found to be negligible compared to the D'yakonov-Perel' mechanism in intrinsic sample. Due to the absence of direct measurement of the electron effective mass in the whole compositional range under investigation, we further explore the effect of a possible variation of electron effective mass on the electron spin relaxation.