Overlap structure of Fano-resonance profiles of excitons in a semiconductor quantum well
The Fano resonance of an exciton in a quantum well of GaAs/Al{sub 0.3}Ga{sub 0.7}As belonging to the {Gamma}{sub 7}{sup +}-irreducible representation is investigated based on the excitonic 4 x 4 Luttinger Hamiltonian. Multichannel scattering problems for the resonance states are solved by virtue of the adiabatic expansion and the R-matrix propagation method, which enable us to implement high-resolution calculations without introducing any empirical broadening parameters. Absorption spectra for excitons are calculated in 100--500-Aa-thick quantum wells, and detailed Fano-resonance profiles for both optically active and inactive exciton states are revealed. Specifically, it is noticed that complicated interference between Fano resonances pertaining to different subbands occurs in a quantum well of more than 350 Aa. A resulting composite profile manifests itself as overlap resonance, accompanying marked changes in a peak height, a width, and an asymmetry pattern from the corresponding isolated profiles. Such changes are evaluated qualitatively by use of Fano's model for one open-channel and two closed-channels. Moreover, quantitative interpretations are also made by employing a time delay given by an eigenphase sum.
- Sponsoring Organization:
- (US)
- OSTI ID:
- 40230918
- Journal Information:
- Physical Review B, Vol. 64, Issue 7; Other Information: DOI: 10.1103/PhysRevB.64.075318; Othernumber: PRBMDO000064000007075318000001; 057127PRB; PBD: 15 Aug 2001; ISSN 0163-1829
- Publisher:
- The American Physical Society
- Country of Publication:
- United States
- Language:
- English
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