Theory of magneto-optical absorption of the quasi-one-dimensional electron gas

In the framework of the current-response scheme we develop the theory of magneto-optical absorption of the quasi-one-dimensional electron gas synthesized in semiconductor quantum-well wires. We calculate the nonlocal magnetoconductivity tensor in the random-phase approximation. The calculations of power absorption are done for normally incident light with electric field vector polarized perpendicular to the wire. It is shown that the absorption peaks arise at the frequencies of the antisymmetric intersubband magnetoplasmons (collective intersubband resonances), for both fundamental and additional antisymmetric modes and thus, only these modes are dipole-active. The strengths of the absorption maxima depend on the magnetic field, and are different for the different modes. In the regions of weak hybridization of collective electron transitions the fundamental modes show a nearly linear increase of the peak height with increasing magnetic field, while the additional modes show maximum absorption in a finite range of magnetic field. The obtained results agree well with the recently observed far-infrared absorption spectra. (C) 1998 Elsevier Science B.V. All rights reserved.