Interplay of Collective Excitations in Quantum-Well Intersubband Resonances

Jianzhong Li, C. Z. Ning

Research output: Contribution to journalArticle

60 Scopus citations

Abstract

Intersubband resonances in a semiconductor quantum well (QW) display fascinating features involving various collective excitations such as Fermi-edge singularity (FES) and intersubband plasmon (ISP). Using a density matrix approach, we treated many-body effects such as depolarization, vertex correction, and self-energy consistently for a two-subband system. We found a systematic change in resonance spectra from FES- to ISP-dominated features, as QW width or electron density is varied. Such an interplay between FES and ISP significantly changes both line shape and peak position of the absorption spectrum. We found that a cancellation of FES and ISP undresses the resonant responses and recovers the single-particle features of absorption for semiconductors with a strong nonparabolicity such as InAs, leading to a dramatic broadening of the absorption spectrum.

Original languageEnglish (US)
JournalPhysical Review Letters
Volume91
Issue number9
DOIs
StatePublished - Aug 26 2003
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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