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Optical and acoustic intersubband plasmons

Optische und akustische Intersubband-Plasmonen
: Rösch, M.; Batke, E.; Köhler, K.; Ganser, P.


epl. A letters journal exploring the frontiers of physics 68 (2004), No.3, pp.440-446
ISSN: 0302-072X
ISSN: 0295-5075
ISSN: 1286-4854
Journal Article
Fraunhofer IAF ()
III-V semiconductor; III-V Halbleiter; heterostructure; Heterostruktur; optical spectroscopy; optische Spektroskopie

Intersubband plasmon modes in a tunneling coupled bilayer system based on a 40nm wide GaAs/Al(0.3)Ga(0.7)As double heterostructure are studied by grating-coupler-assisted far-infrared spectroscopy. Both the charge density and the space symmetry of the bilayer can be tuned via front gate and are determined by means of magnetotransport measurements. We observe a strong-coupling behavior of the bilayer intersubband plasmon branches, resulting in the novel feature of optical and acoustic intersubband modes. The transmission spectra are excellently described by the self-consistently calculated absorption of the bilayer electron gas. Our theory in the framework of the current-response scheme takes into account the optics of the grating coupler and includes the interaction between the quasi-two-dimensional plasmon excitations.