Bistable tunneling current through a quantum dot array junction

We investigate the tunneling current through a six-fold degenerate $p$ --like states of a one- dimensional (1D) or two-dimensional (2D) quantum dot (QD) array in the x-y plane. Due to the coupling of$p_x $ and $p_y $orbitals at neighboring QDs, a 1D or 2D conduction band ($\varepsilon _p )$ is formed, whereas the $p_z $ orbitals remain localized due to their weak in-plane coupling. The on-site repulsive Coulomb interaction in the $p_z $ levels ($U)$ and that between the $p_z $ level and $p_x $/$p_y $ level ($U_{dc} )$ are taken into account in an extended Anderson model, which is used to investigate the tunneling characteristics of the system. Tunneling current through localized $p_z $ state is calculated in the framework of the Green function technique. Due to the effect of $U_{dc} $, the 1D/2D conduction band states are shifted by a self-energy term $2NU_{dc} $. We find that bistable current can be observed for this system in the Coulomb blockade regime, which makes the system a valid candidate for ultra high-density memory device.