Nonlinear behaviour of the high-frequency conductivity of the 2DEG in the quantum hall regime as studied by an acoustical method

摘要

Surface acoustic wave (SAW) attenuation dependence in a GaAs/AlGaAs heterostructure on temperature T, magnetic field and SAW intensity W is studied. For filling factors v>6 the SAW attenuation dependence on temperature in the vicinity of sigma _(xx) minima is well fitted with a power series, whereas for v<5, approximation is achieved with an exponent. The attenuation factor dependence on SAW intensity for v>6 could be attributed to the 2DEG heating in the electric field of a SAW. The electronic temperature of 2DEG was determined from the correlation of the SAW attenuation dependencies on T and W. The attenuation factor dependence on SAW intensity for v<5could be due to the effect of thermo-electronic ionization.