COMPUTER SIMULATION OF ELECTRON TRANSPORT IN A SEMICONDUCTOR QUANTUM WIRE
The picture is a representation of the wave function of an electron traveling along a
semiconductor quantum wire in a magnetic field and encountering a peanut-shaped artificial
impurity or "antidot". It is based on a computer simulation by George Kirczenow of a device
fabricated and studied experimentally by Andy Sachrajda and his collaborators at NRC in Ottawa.
What you are seeing is an electron wave travelling from left to right along the top edge of the
picture. When it hits the artificial impurity most of the electron wave is reflected, and then
deflected downwards by the magnetic field towards the bottom of the antidot. There most of the
wave is again reflected and travels out of the picture from right to left along the bottom edge
in a complicated interference pattern. But a small part of the wave leaks past the artificial
impurity at the top and bottom. At the top this transmitted wave continues to the right in the
form of the dark undulating ribbon. The transmitted wave at the bottom is deflected by the
magnetic field and because of that returns to the top of the artificial impurity along the
curved path on the right. Part of this path is darker and part is lighter than the background.
Some of this returning wave then leaks back to the left above the artificial impurity, thus
forming a closed resonant orbit whose signature is detected experimentally as a peak in the
measured conductance of the device.