DC and far-infrared experiments on one-dimensional multi-layered quantum wires

Abstract

One-dimensional electronic systems (1DES) have been realized by ultrafine mesa etching of modulation doped GaAs/AlGaAs heterostructures and multi quantum well systems. The electronic properties of these single and multi-layered quantum wires have been characterized by dc magneto transport measurements. Typical energy separations of 1 to 3 meV for the 1D subbands were found in electron channels of 400 to 150 nm width. The 1D subband separation is not directly observed in the far infrared (FIR) response, rather, resonances at significantly higher frequencies are observed, indicating a dominant influence of collective effects. This gives the FIR resonances the character of plasmon modes which are localized by the microstructure. The plasmon character is in particular manifested by the observation of layer-coupled plasmon modes with n resonances in an n-layered quantum wire.