Popis: |
We have studied the cyclotron resonance (CR) of high mobility 2D electrons in GaAs/AlGaAs heterostructures at 2.3 ≤T≤4.2 K, using far infrared lasers with wavelengths ranged from 96.52 to 512.88 μm. The CR experiments are carried out in the low density range, 1 × 1010 ≲ ns ≤1.2 × 1011 cm−2, which is controlled by using either a back gate or a front gate. Using back gate. Using back gate, the effective mass is constant after the nonparabolicity correction and the CR lines are extremely narrow. The extracted CR lifetime, τCR, depends on ns following τCR ∝ ns1.9 ± 0.1 in the extreme quantum limit, 0.08 < v < 0.4. On the other hand, when a front gate is used, the CR lines show strong inhomogeneous broadening, which can be explained by assuming that { 30% of 2D area is not affected by the gate voltage. |