Multidielectric response of a two-dimensional electron gas in tilted magnetic fields

The infrared transmission of a multilayer system containing a two-dimensional electron gas is evaluated as a function of magnetic field for a configuration where the multilayer axis is tilted with respect to the direction of the applied magnetic field. The specific case of a doped quantum well is considered and it is shown that under the tilted configuration the cyclotron resonance couples to the mixed plasmon-intersubband mode by pure dielectric effects.

Figure 1

Energies of the minima of transmission, at $1.8\mathrm{K}$, of a two-dimensional electron gas imbedded in a $\mathrm{GaAs}$ quantum well, of width $13\mathrm{nm}$, around the TO energy of this compound, as a function of the component of the field perpendicular to the QW plane $B_{\perp }$. These data are obtained in PF configuration (open dots) and in the TF configuration for an angle $\theta =26.5°$ (full dots). Full triangles and crosses are the observed phonon structures corresponding to the TO and LO (slab modes) of the structure, respectively.

Figure 2

Absolute transmission spectrum (empty dots), at $1.8\mathrm{K}$, of a two-dimensional electron gas imbedded in a $\mathrm{GaAs}$ quantum well, of width $13\mathrm{nm}$, in a TF configuration with an angle $\theta =26.5°$ and $B_{\perp }=20.9\mathrm{T}$. The dotted lines refer to the LO energies of $\mathrm{GaAs}$ and $\mathrm{AlAs}$ and the dashed lines to the two cyclotron like transitions CR1 and CR2 (see text). The continuous line is the fit of the model to the data.

Figure 3

Fit of the relative transmission curves at $\theta =26.5°$ for different values of $B_{\perp }$. The curves are shifted for clarity. Empty dots are experimental points and the full continuous curves the corresponding calculated relative transmission spectra.

Figure 4

Variation of the zeros of the component ${\epsilon }_{zz}$ for a TF configuration with $\theta =30°$ as a function of $B_{\perp }$. Full lines are related to an intersubband energy $\hslash \Omega =65\mathrm{meV}$ and dotted lines to $\hslash \Omega =30\mathrm{meV}$.