Cyclotron and combined phonon-assisted resonances in the double-well heterostructure In_(0.65)Ga_(0.35)As/In_(0.52)Al_(0.48)As at megagauss magnetic fields

摘要

Experiments on resonances of conduction electrons in InGaAs/InAlAs double quantum wells at megagauss magnetic fields in the Faraday geometry are reported. We observe four magneto-optical transitions in 2D systems: two cyclotron resonances assisted by emissions of InAs-like and GaAs-like optic phonons, a combined (cyclotron-spin) resonance, and the combined resonance assisted by an emission of InAs-like phonon. The observations are very well described for three laser frequencies with the use of an eight-band (three level) k . p model, taking into account position- and energy-dependent effective masses and spin g factors. The observation of combined resonances in the Faraday configuration indicates that the energy subbands in the investigated quantum wells are not only markedly nonparabolic but also slightly nonspherical. It is indicated that the observations are possible due to the application of very high magnetic fields.