| 摘要 |
An apparatus includes a substrate having a planar top surface, a sequence of crystalline semiconductor layers located on the planar surface, and first and second sets of electrodes located over the sequence. The sequence of crystalline semiconductor layers has a 2D quantum well therein. The first set of electrodes border opposite sides of a lateral region of the sequence and are controllable to vary a width of a non-depleted portion of the quantum well along the top surface. The second set of electrodes border first and second channels between the lateral region and first and second adjacent lateral areas of the sequence and are controllable to vary widths of non-depleted segments of the quantum well in the channels. The electrodes are located such that straight lines connecting the first and second lateral areas via the channels either pass between one of the electrodes and the substrate or are misaligned to an effective [1 1 0] lattice direction of the sequence. |
