Negative rf Conductivity Caused by Polar Optical Phonons and Ionized Impurities in a Longitudinal Magnetic Field

抄録

High frequency electrical conductivity is calculated in the presence of a static electric and magnetic fields both parallel to the rf electric field. Displaced Maxwellian distribution is assumed. It has been found that the rf conductivity becomes negative when the drift velocity exceeds 0.85 times the thermal velocity if polar optical phonon scattering is taken into account and that 0.65 times the thermal velocity if screened Coulomb scattering is taken into account. Furthermore fluctuation of the electron distribution is computed in the velocity space.