ABSTRACT
Backward-wave tubes are used to study the spectra of cyclotron resonance in the range of 160 to 700 GHz in the AlSb/InAs/AlSb quantum well (QW) heterostructures in wide range of two-dimensional electron gas concentration from 2.7×1011 to 8×1012 cm−2 at T = 4.2 K. A significant increase in the cyclotron mass (from 0.03m 0 to 0.06m 0) is observed as the electron concentration (and, correspondingly, the Fermi energy) increases, which is typical of semiconductors with a nonparabolic dispersion relation. In the high mobility (4×103 cm−2/V·s) undoped sample with electron concentration 6×1011 cm−2 a remarkable CR line splitting was discovered in moderate magnetic fields 5 to 7 kOe accompanied by distinct Shubnikov-de Haas-type oscillations of the absorption. The effect is attributed to the Rashba splitting of the electron states in built-in electric field.
