Oscillator-strength modification of Stark ladder transitions due to resonance-induced wavefunction delocalization in a GaAs/AlAs superlattice under the electric field

Citation
T. Nogami et al., Oscillator-strength modification of Stark ladder transitions due to resonance-induced wavefunction delocalization in a GaAs/AlAs superlattice under the electric field, PHYSICA E, 9(2), 2001, pp. 236-242
Citations number
18
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
PHYSICA E
ISSN journal
1386-9477 → ACNP
Volume
9
Issue
2
Year of publication
2001
Pages
236 - 242
Database
ISI
SICI code
1386-9477(200102)9:2<236:OMOSLT>2.0.ZU;2-9
Abstract
Spatially direct and indirect Stark ladder optical transitions and their el ectric-field-induced evolution have been investigated in a GaAs/AlAs (L-Z = 6.4 nm/L-B = 0.9 nm) superlattice by low-temperature photocurrent spectros copy. When the ground and first excited electron Stark ladder states resona te between the nearest-neighbor wells, it is found that oscillator strength s of the direct (n = 0) and indirect (n = +1) Stark ladder transitions are strongly modified, accompanying enhanced anticrossings. The observed modifi cation effects on the oscillator strength of the transitions are rigorously explained in terms of the wave function delocalization after the complete Wannier-Stark localization due to the resonant couplings between the adjace nt wells, based on transfer matrix calculations of the ladder eigenstate an d the wave function overlap integrals between the electron and hole subband states. (C) 2001 Elsevier Science B.V. All rights reserved.