DC AND HIGH-FREQUENCY TRANSPORT IN QUASI-ONE-DIMENSIONAL QUANTUM WIRES WITH ROUGH BOUNDARIES

We fabricate quasi-one-dimensional electron wires by low-energy ion-be am exposure in AlxGa1-xAs/GaAs heterojunctions and study their transpo rt properties in the low- and high-frequency domain. Typical widths of our electron wires range from 100 nm to 1 mum. The static and far-inf rared (FIR) conductivities are measured at low temperatures (T less-th an-or-equal-to 4.2 K) and high magnetic fields (B less-than-or-equal-t o 12 T). The experiments demonstrate that in these wires a large propo rtion of the boundary scattering events is diffuse. The FIR conductivi ty exhibits intersubband and intrasubband plasmon resonances. The line widths of these excitations reflect an intriguing anisotropy that aris es from a mode-dependent sensitivity of these high-frequency excitatio ns on the boundary roughness. Photoluminescence experiments indicate t hat the confinement is accompanied by creation of defects in the plane of the electron system that strongly reduce the mobility of the elect rons in the areas exposed to the ion beam.