Dynamics of Quantal Heating in Electron Systems with Discrete Spectra

الأصل · EN

The temporal evolution of quantal Joule heating of 2D electrons in GaAs quantum well placed in quantizing magnetic fields is studied using a difference frequency method. The method is based on measurements of the electron conductivity oscillating at the beat frequency f=f₁-f₂ between two microwaves applied to 2D system at frequencies f₁ and f₂. The method provides direct access to the dynamical characteristics of the heating and yields the inelastic scattering time τin of 2D electrons. The obtained τin is strongly temperature dependent, varying from 0.13 ns at 5.5K to 1 ns at 2.4K in magnetic field B=0.333T. When temperature T exceeds the Landau level separation the relaxation rate 1/τin is proportional to T², indicating the electron-electron interaction as the dominant mechanism limiting the quantal heating. At lower temperatures the rate tends to be proportional to T³, indicating considerable contribution from electron-phonon scattering.