COUPLING OF PLASMA MODES IN A SI ACCUMULATION LAYER

We perform a realistic calculation of the plasma-mode spectrum for a Si(100) accumulation layer as a function of electron density, ns, and [100] stress, P. For this system, the strong coupling of the intrasubband- and first-intersubband plasma modes is revealed through an avoided crossing of the mode dispersions. We provide a more fundamental illustration of this phenomenon by calculating, as well, the reflectivity spectra, and we show that a strong exchange of oscillator strengths between the two modes occurs. We obtain very good quantitative agreement with the experimental results of Oelting, Heitmann, and Kotthaus [Phys. Rev. Lett. 56, 1846 (1986)]. © 1990 The American Physical Society.