Bunching of Carriers in Momentum Space under Crossed Magnetic and Intense Microwave Fields in Semiconductors

Abstract

The motion of a carrier in momentum space is examined in detail for the case that an intense microwave electric field and a static magnetic field perpendicular to it are applied to semiconductors in which the predominant scattering process is the optical phonon emission. The motion changes the type in a systematic way depending on the strengths of the fields. Particularly in intermediate magnetic field range, the motion rapidly converges to a terminal motion independent of the initial condition, leading to a bunching of the carriers in the momentum space. The convergence becomes slow as the magnetic field is decreased. In strong magnetic fields, the motion becomes of long period or chaotic. The type of the motion changes periodically with the electric field. The calculation is carried out for two waveforms, square and sinusoidal. The results are very similar to each other as for the bunching, implying its generic property.