Hot Electron Effect in Cyclotron Resonance of Germanium

The experiment on cyclotron resonance of electrons in nearly intrinsic n -type germanium with donor concentration of 7×10 12 cm -3 was made at 1.6°K, making use of 6 mm microwave. The line shape as well as line width was measured as a function of power of microwave. For relatively high power (more than ten microwatts) the line width increases as ( P / m * ) 1/2,5 , where P is the microwave power and m * is the mass along the direction of microwave electric field. The line shape is like Gaussian for higher power, while for low power it is Lorentzian. These facts were reasonably interpreted in term of rise of effective electron temperature due to the microwave absorption.