https://doi.org/10.1140/epjb/e2003-00152-1
Collective electronic excitations in a semiconductor superlattice in the Landau and Wannier-Stark ladder regime
1
Department of Physics, N.P. Ogarev Mordovian State University,
Saransk 430000, Russia
2
Department of Informatics and Computer Science, Mordovian State
Pedagogical Institute, Saransk 430007, Russia
3
Department of Chemistry, N.P. Ogarev Mordovian State University,
Saransk 430000, Russia
Corresponding author: a 612033@inbox.ru
Received:
29
August
2002
Revised:
25
February
2003
Published online:
4
June
2003
Using a mean-field approximation, we have developed a systematic treatment of
collective electronic modes in a semiconductor superlattice (SL) in the
presence of strong electric and magnetic fields parallel to the SL axis. The
spectrum of collective modes with zero wavevector along the SL axis is shown to
consist of a principle magnetoplasmon mode and an infinite set of
Bernstein-like modes. For non-zero wavevector along the SL axis, in addition to
the cyclotron modes, extra collective modes are found at the frequencies , which we call cyclotron-Stark modes (
and
are respectively the cyclotron and Stark frequencies, N and
M are integer numbers). The frequencies of the modes propagating in
“oblique” direction with respect to the SL axis show oscillatory behavior as
a function of electric field strength. All the modes considered have very weak
spatial dispersion and they are not Landau damped. The specific predictions
made for the dispersion relations of the collective excitations should be
observable in resonant Raman scattering experiments.
PACS: 73.20.Mf – Collective excitations (including excitons, polarons, plasmons and other charge-density excitations) / 73.20.Dx – Electron states at surfaces and interfaces
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2003