Magneto-intersubband zener tunneling in a wide GaAs quantum well at high filling factors

The dependence of the differential resistance $r_{xx}$ on the dc current density $J_{dc}$ in a wide GaAs quantum well with two occupied size quantization subbands has been investigated at the temperature $T = 4.2$ K in the magnetic fields $B< 1$ T. A peak, whose position is given by the relation $2R_{c}eE_{\rm H}=\hbar\omega_{c}/2$, where $R_{c}$ is the cyclotron radius, $E_{\rm H}$ is the Hall electric field, and $\omega_{c}$ is the cyclotron frequency, has been observed in the $r_{xx}(J_{dc})$ curves at high filling factors. The experimental results are attributed to Zener tunneling of electrons between the Landau levels of different subbands.