MAGNETOOPTICAL ABSORPTION-SPECTRA OF PERIODIC SUPERLATTICES UNDER INPLANE MAGNETIC-FIELDS

An extensive theoretical study of the magneto-optical absorption spect ra of periodic GaAs-(Ga, Al)As superlattices under magnetic fields par allel to the heterostructure interfaces is presented within the framew ork of the effective-mass approximation. ?he absorption coefficient as sociated with interband transitions between valence-hole and conductio n-electron magnetic levels is calculated by considering an expansion o f the envelope wavefunctions in terms of sine functions and by adoptin g a parabolic-band model for both electrons and holes. Results for the theoretical magneto-optical interband absorption spectra for varying in-plane magnetic fields compare qualitatively well with various exper imental measurements. We present a detailed analysis of the effects of off-diagonal interband transitions involving conduction and valence L andau levels n and n', respectively, with Delta n not equal 0, and it is unambiguously shown that off-diagonal transitions may introduce sig nificant contributions and extra features in the magneto-optical absor ption spectra.