Reflection and refraction of ballistic electrons through different carrier concentration regions

Transmission and reflection characteristics of ballistic electrons are studied in a macroscopic four-terminal square device with a strip Schottky gate placed so as to bisect the device. Since the gate is negatively biased, a bend resistance peak at zero magnetic field, which is induced by ballistic electron injection into an opposite voltage probe, varies from positive to negative, and a magnetic focusing peak shifts to a lower field. These phenomena arise from the reflection of ballistic electrons crossing regions of different electron densities. The transmission and reflection probabilities are determined as a function of gate voltage, and are related to the change in the refractive index of ballistic electrons.