MECHANISM OF APPARENT REFLECTION OF ELECTRONS FROM EXTRA PROBES INVESTIGATED BY THE MAGNETIC ELECTRON-FOCUSING EFFECT

The magnetic electron-focusing effect (MEFE) has been investigated in mesoscopic multiterminal samples of GaAs/AlxGa1-xAs heterostructures. The MEFE peaks are clearly observed even in a configuration where elec trons seem to be reflected from an extra probe between an emitter and a collector probe. To clarify the reflection mechanism, the ''reflecti on'' peaks are studied in the samples with variously shaped extra prob es and in the samples with two extra probes connected by a byway chann el or an external circuit. In the reflection events, the electrons dif ferent from the electrons injected into the extra probe should be emit ted from the extra probe, since the chemical potential of the extra pr obe becomes higher due to the accumulation of electrons in the extra p robe.