1D-to-2D tunneling in electron waveguides

We present a comprehensive experimental study of the tunneling and transport characteristics of split-gate ‘‘leaky’’ one-dimensional (1D) electron waveguides implemented in ${\mathrm{Al}}_{\mathit{x}}$ ${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As/GaAs heterostructures. In a leaky electron waveguide, electrons can tunnel out of the 1D channel through a thin side wall barrier into an adjacent 2D electron bath. A sharp peak and valley structure is observed in the 1D-to-2D tunneling current as the carrier concentration is modulated in the 1D waveguide through the field-effect action of the split gates. A semiclassical model confirms that the tunneling features originate from the 1D subbands in the channel.