The DC and AC conductivities of the n-GaAs/AlAs heterostructure with two filled size quantization levels are studied within a wide magnetic field range. The electron spectrum of such heterostructure is characterized by two subbands (symmetric S and antisymmetric AS), separated by the band gap Δ₁₂ = 15.5 meV. It is shown that, in the linear regime at the applied magnetic field B > 3 T, the system exhibits oscillations corresponding to the integer quantum Hall effect. A quite complicated pattern of such oscillations is well interpreted in terms of transitions between Landau levels related to different subbands. At B < 1 T, magneto-intersubband resistance oscillations (MISOs) are observed. An increase in the conductivity with the electric current flowing across the sample or in the intensity of the surface acoustic wave (SAW) in the regime of the integer quantum Hall effect is determined by an increase in the electron gas temperature. In the case of intersubband transitions, it is found that nonlinearity cannot be explained by heating. At the same time, the decrease in the AC conductivity with increasing SAW electric field is independent of frequency, but the corresponding behavior does not coincide with that corresponding to the dependence of the DC conductivity on the Hall voltage E_y.

中文翻译：

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两子带n -GaAs / AlAs异质结构中的非线性AC和DC电导率

研究了在宽磁场范围内具有两个填充尺寸量化级的n -GaAs / AlAs异质结构的DC和AC电导率。这种异质结构的电子光谱的特征在于两个子带（对称小号和反对称AS）中，由带隙Δ分离₁₂ = 15.5兆电子伏。结果表明，在施加磁场B > 3 T的线性状态下，系统表现出与整数量子霍尔效应相对应的振荡。根据与不同子带有关的朗道能级之间的转换，可以很好地解释这种振荡的非常复杂的模式。在B<1 T，观察到磁间子带电阻振荡（MISO）。通过电子气体温度的升高来确定随着整数电流霍尔效应的作用，电流流经样品的电导率的增加或表面声波（SAW）的强度的增加。发现在子带间过渡的情况下，非线性不能通过加热来解释。同时，随着SAW电场的增加，交流电导率的降低与频率无关，但是相应的行为与直流电导率对霍​​尔电压E _y的依赖关系不一致。