Controlled one-dimensional channel in a quantum point contact with a triple-gate structure

We have studied the electrical transport characteristics of a GaAs quantum point contact with a triple-gate structure at the front surface. Controlling applied voltage to these three gates and, in addition, backgate voltage to control electron density, a potential shape of the one-dimensional channel can be modified, resulting in the various transport characteristics. When the center gate (CG) voltage (V
cg
) is negative, two parallel channels appear in the QPC. Under the positive V
cg
, the parallel channel changes to the single channel. Moreover, an oscillatory structure appears on the plateau in the large V
cg
region, suggesting a formation of a rectangular shape potential in the one-dimensional channel.