Electrically controlled switching between spatially separated conducting channels in a quantum point contact

We demonstrate transverse magnetic focusing of electrons in semiconductor devices consisting of two trenched-type quantum point contacts (QPC) acting as an injector and a detector. The peak in the detector voltage,  corresponding to the penetration of injected electrons into the detector, is observed. Applying the voltage difference between injector side gates is found to cause an abrupt shift of the peak position on the magnetic field scale. This shift can be explained by switching between spatially separated channels inside the multi-well potential formed inside a QPC-injector.