Anomalous magnetic suppression of spin relaxation in a two-dimensional electron gas in a GaAs/AlGaAs quantum well

Motion of an electron and precession of its spin are tightly interrelated via the spin-orbit interaction. In a two-dimensional magnetized system, the electron occupies a cyclotron orbit, which limits spin deviation and suppresses spin relaxation. Starting with this classical scenario at low magnetic fields, the authors unexpectedly encounter a peculiar spin relaxation at higher fields. It reveals an anomaly in the electron diffusion that was previously observed in magnetized plasmas and has found no unique explanation so far. In the quantum limit, the authors find a strong enhancement of the longitudinal spin relaxation time when Landau levels are fully occupied by electrons.