Cyclotron Resonance Line Broadening due to Carrier-Carrier Interaction in Germanium

Abstract

The resonance line broadening due to carrier-carrier interaction in cyclotron resonance spectrum in pure germanium was investigated by increasing the density of photo-generated carriers up to 10¹⁴ cm⁻³. Measuring temperature ranged from 1.6°K to 15°K. The carrier density was estimated by combining the plasma shift of resonance line with the area under the absorption curve. While at high temperature the increment of the line width is approximately proportional to the carrier density, it is proportional to the square root of the carrier density at low temperature. It was found that the behavior at high density was well interpreted by the term of the scattering process by another carrier obeying the Brooks-Herring formula with the use of reduced mass of two interacting carriers. On the other hand, the broadening at low temperature for low density is rather inhomogeneous in the sense that the cyclotron frequency is randomly modulated by the Coulomb field due to another carrier.