The Collective Excitations in Quasi-N-Dimensional (N ≤ 2) Electron-Gas Systems: The Competition Between the Inelastic Electron Scattering and the Inelastic Light Scattering

The most fundamental approach to an understanding of electronic, optical, and transport phenomena in condensed matter physics is generally founded on two experiments: the inelastic electron scattering and the inelastic light scattering. We embark on establishing
a systematic framework for the theory of inelastic electron scattering and of inelastic light scattering from the electronic excitations in GaAs/Ga1−xAlxAs quasi-N-dimensional (N ≤ 2) electron systems (QNDES). To this end, we start with the Kubo’s correlation function
to derive the generalized dielectric function and the inverse dielectric function within the framework of random-phase approximation.
After trying and testing the general analytical results, we compute the full excitation spectrum, loss functions for the inelastic electron scattering, and Raman intensity for the inelastic light scattering. It is observed that the dominant contribution to both the loss peaks
and the Raman peaks comes from the collective (plasmon) excitations. This leads us to infer that the inelastic electron scattering can
be a potential alternative of the inelastic light scattering for investigating collective excitations in QNDES.[See, e.g., M.S. Kushwaha,
AIP Advances 2, 032104 (2012); 3, 042103 (2013); 4, 127151 (2014); 6, 035014 (2016).]