Resonant tunneling and Fano resonance in quantum dots with electron-phonon interaction

Akiko Ueda, Mikio Eto

Research output: Contribution to journalArticle

46 Citations (Scopus)

Abstract

We theoretically study the resonant tunneling and Fano resonance in quantum dots with electron-phonon (e-ph) interaction. We examine the bias-voltage (V) dependence of the decoherence, using the Keldysh Green function method and perturbation with respect to the e-ph interaction. With optical phonons of energy ω0, only the elastic process takes place when eV< ω0, in which electrons emit and absorb phonons virtually. The process suppresses the resonant amplitude. When eV> ω0, the inelastic process is possible, which is accompanied by real emission of phonons. It results in the dephasing and broadens the resonant width. The bias-voltage dependence of the decoherence is not easy to obtain by the canonical transformation method of the e-ph interaction with neglecting the renormalization of tunnel coupling. With acoustic phonons, the asymmetric shape of the Fano resonance grows like a symmetric one as the bias voltage increases, in qualitative accordance with experimental results.

Original languageEnglish
Article number235353
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume73
Issue number23
DOIs
Publication statusPublished - 2006

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Resonant tunneling
Electron-phonon interactions
resonant tunneling
Phonons
Bias voltage
electron phonon interactions
Semiconductor quantum dots
phonons
quantum dots
electric potential
Green's function
tunnels
Tunnels
Green's functions
Acoustics
perturbation
acoustics
energy

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

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abstract = "We theoretically study the resonant tunneling and Fano resonance in quantum dots with electron-phonon (e-ph) interaction. We examine the bias-voltage (V) dependence of the decoherence, using the Keldysh Green function method and perturbation with respect to the e-ph interaction. With optical phonons of energy ω0, only the elastic process takes place when eV< ω0, in which electrons emit and absorb phonons virtually. The process suppresses the resonant amplitude. When eV> ω0, the inelastic process is possible, which is accompanied by real emission of phonons. It results in the dephasing and broadens the resonant width. The bias-voltage dependence of the decoherence is not easy to obtain by the canonical transformation method of the e-ph interaction with neglecting the renormalization of tunnel coupling. With acoustic phonons, the asymmetric shape of the Fano resonance grows like a symmetric one as the bias voltage increases, in qualitative accordance with experimental results.",
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