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Electric‐Field Effects on the Band‐Edge States of GaAs/AlAs Coupled Quantum Wells
Author(s) -
Ribeiro F.J.,
Capaz R.B.,
Koiller B.
Publication year - 2002
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/1521-3951(200207)232:1<148::aid-pssb148>3.0.co;2-i
Subject(s) - electric field , heterojunction , quantum well , condensed matter physics , atomic orbital , electron , perpendicular , supercell , quantum confined stark effect , physics , optics , stark effect , quantum mechanics , geometry , laser , thunderstorm , mathematics , meteorology
Optical experiments on electric field tunable AlAs/GaAs coupled quantum wells demonstrate that the optical nature of these structures can be directly controlled by an applied electric field. In this work we are concerned with calculation and analysis of the first electron and hole states in these structures. We take into account the effects of the heterostrucuture geometry and of the external uniform electric field applied perpendicularly to the layers, which may lead to an anticrossing of low‐lying electron levels in the system. Calculations are performed within the tight‐binding supercell formalism with interactions between atomic orbitals up to second nearest neighbors. Our results show that for GaAs layers less than ≈30 Å wide, the application of electric fields turns the heterostructures from type II to type I behavior. Our estimated value of the electric field intensity needed to realize this transition is in good agreement with the experimental results for comparable heterostructure geometry.