We report the observation of ballistic transport of upper subband electrons in a two-dimensional electron system (2DES) confined to a square quantum well with two occupied electrical subbands. We have performed two types of experiments. In the first type, we use a specially designed transverse magnetic focusing device in which the usual reflecting barrier is replaced by a surface-gate-induced, tunable potential barrier to selectively reflect and magnetically focus the upper subband electrons. In the second type of experiment, we create a surface-gate-induced, periodic potential in a double-subband-occupied 2DES and measure the magnetoresistance along the modulation direction. Fourier analysis is used to separate the commensurability oscillations originating from ballistic electrons of different subbands.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering
- 2d electron gas
- Ballistic transport
- Double subband system