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摘要
The temporal evolution of quantal Joule heating of two-dimensional (2D) electrons in a 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 = f(1) - f(2) between two microwaves applied to the 2D system at frequencies f(1) and f(2). The method provides direct access to the dynamical characteristics of the heating and yields the inelastic-scattering time tau(in) of 2D electrons. The obtained tau(in) is strongly temperature dependent, varying from 0.13 ns at 5.5 K to 1 ns at 2.4 K in magnetic field B = 0.333 T. When the temperature T exceeds the Landau-level separation, the relaxation rate 1/tau(in) is proportional to T-2, indicating electron-electron interaction as the dominant mechanism limiting the quantal heating. At lower temperatures, the rate tends to be proportional to T-3, indicating considerable contribution from electron-phonon scattering.
- 出版日期2015-5-27
