Magnetic field effect on diffusion of photogenerated holes in a mesoscopic GaAs channel

The effect of the magnetic field on diffusion of the photogenerated holes was studied in a mesoscopic channel formed in a high-mobility GaAs quantum well where the electron-hole plasma reveals hydrodynamic properties. The reported results demonstrate that the magnetic field leads to a significant asymmetry of the diffusion profile, which depends on the direction of the magnetic field. According to the presented results, the observed asymmetry is due to the entrainment of holes by the electron Hall current. As a result, a magnetic-field-induced spatial separation of the diffusion of heavy and light holes was found. The valve effect, which controls the number of photogenerated light holes reaching the collection probes, is observed when the current through the collection probes is varied.