5 research outputs found
Optical response of two-dimensional electron fluids beyond the Kohn regime: strong non-parabolic confinement and intense laser light
We investigate the linear and non-linear optical response of two-dimensional
(2D) interacting electron fluids confined by a strong non-parabolic potential.
We show that such fluids may exhibit higher-harmonic spectra under realistic
experimental conditions. Higher harmonics arise as the electrons explore
anharmonicities of the confinement potential (electron-electron interactions
reduce this non-linear effect). This opens the possibility of controlling the
optical functionality of such systems by engineering the confinement potential.
Our results were obtained within time-dependent density-functional theory,
employing the adiabatic local-density approximation. A classical hydrodynamical
model is in good agreement with the quantum-mechanical results.Comment: 4 pages, 4 figure
Elementary electronic excitation from a two-dimensional hole gas in the presence of spin-orbit interaction
We present a theoretical study of the elementary electronic excitation
associated with plasmon modes in a two-dimensional hole gas (2DHG) in the
presence of spin-orbit (SO) interaction induced by the Rashba effect. The
calculation is carried out using a standard random-phase-approximation
approach. It is found that in such a spintronic system, plasmon excitation can
be achieved via intra- and inter-SO electronic transitions around the Fermi
level. As a result, the intra- and inter-SO plasmon modes can be observed. More
importantly, the plasmon modes induced by inter-SO transition are optic-like
and these modes can be directly applied to identify the Rashba spin splitting
in 2DHG systems through optical measurements. The interesting features of the
plasmon excitation in a spin split 2DHG are analyzed and discussed in details.
Moreover, the results obtained for a 2DHG are compared with those obtained for
a spin-splitting 2DEG reported very recently.Comment: 17 pages and 6 figure