Shubnikov–de Haas oscillations in 2D electron gas with anisotropic mobility

Shubnikov-de Haas oscillations in selectively doped GaAs single quantum wells with AlAs/GaAs superlattice barriers has been studied at temperature $T= 4.2$ K in magnetic fields $B <1$T. High-mobility heterostructures with thin spacer had been grown by molecular-beam epitaxy on $(001)$ GaAs substrates. The mobilities of two-dimensional electron gas measured in two crystallographic directions $[110]$ and $[\bar110]$ differ from each other more than $50$%. Properly adapted expression for Shubnikov-de Haas oscillations amplitudes in anisotropic samples has been used for correct analysis of this oscillations. It was stated that quantum life-time in our heterostructures as measured by Shubnikov–de Haas oscillations on Hall bars oriented in the directions $[110]$ and $[\bar110]$ varies less than $5$%. Obtained results show that quantum life-time in two-dimensional electron system with anisotropic mobility is isotropic with aforementioned accuracy.