THz photocurrent magneto-oscillations in GaN-based asymmetric grating gate structures

We report THz induced ratchet photocurrent in AlGaN/GaN heterostructures superimposed with asymmetric dual-grating gate structure. The photocurrent shows giant magneto-oscillations in the regime of high magnetic fields. Peculiarly, the envelope of these oscillations exhibits large beatings as a function of the magnetic field. We demonstrate experimentally and theoretically that the beatings are caused by the spin-orbit interaction in GaN conduction band. Our results show how THz photoconductivity can be used for studies of spin dependent effects in GaN-based materials.