Magnetotransport and cyclotron resonance in AlAs quantum wells

We have made the first measurements of cyclotron resonance and the Shubnikov-de Haas effect in two-dimensional electronic system confined to AlAs. Cyclotron resonance data show that the effective mass for (100)-oriented samples (0.5m0) is larger than for (111)-oriented samples (0.41m0). This indicates that the X point ellipsoids with their long axes parallel to the interface are occupied. This may be due to compressive stress in the AlAs. From the temperature and magnetic field dependence of the Shubnikov-de Haas oscillations we have also determined the effective mass (m(111)* = 0.49m0; m(100)* = 0.60m0) and the effective g-factor (g* = 3.1-3.4). We find fairly good agreement between measured and calculated values. © 1987.