Plasmon-phonon coupling in lead salt semiconductor quantum well

The dispersion spectrum peculiarities of intrasubband plasmon-phonon modes applied to realistic narrow-gap EuS / PbS / EuS quantum well are investigated depending on the interplay between the system key parameters, such as quantum well thickness and electron gas density. As follows, the strong mode coupling takes place already for typical moderate 2D densities due to the dielectric confinement effect. The strong dependence of the phonon-like coupled mode damping on the QW width is received in contrast to the plasmon - like mode. The numerical results for the energy-loss function and the oscillator strength of the plasmon-like and phonon-like peaks are also presented. It is shown that in the long wavelength limit a plasmon-like coupled mode contribution in this realistic structure is deeply suppressed and the actual oscillator strength on the whole is connected with the phonon-like part.