### Abstract

We theoretically study transport properties of coupled quantum dots in parallel in the presence of electron-phonon (e-ph) interaction. Nonequilibrium transport under finite bias is calculated using the Keldysh Green function method. Firstly, we examine a double-dot interferometer with a penetrating magnetic flux (Aharonov-Bohm phase φ) between the two quantum dots. The differential conductance shows a sharp dip between double resonant peaks, as a function of energy levels in the quantum dots, when the two dots are equivalently coupled to external leads and 0 < φ < π. The e-ph interaction significantly decreases the dip, reflecting an emission of phonons from one of the quantum dots. This dephasing effect is more prominent under larger bias voltage. Secondly, we study a T-shaped double-dot system in which one of the dots is connected to the external leads (dot 1) and the other is disconnected (dot 2). The differential conductance shows a dip between two resonant peaks, as in the double-dot interferometer. The dip is weakly reduced by an emission of phonons from dot 2. Phonon emission from dot 1 does not result in dephasing and hence does not influence the dip. Therefore the dip of the conductance is more robust against the e-ph interaction in the T-shaped double-dot system than in the double-dot interferometer.

Original language | English |
---|---|

Article number | 119 |

Journal | New Journal of Physics |

Volume | 9 |

DOIs | |

Publication status | Published - 2007 May 9 |

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### ASJC Scopus subject areas

- Physics and Astronomy(all)

### Cite this

**Nonequilibrium transport through coupled quantum dots with electron-phonon interaction.** / Ueda, Akiko; Eto, Mikio.

Research output: Contribution to journal › Article

}

TY - JOUR

T1 - Nonequilibrium transport through coupled quantum dots with electron-phonon interaction

AU - Ueda, Akiko

AU - Eto, Mikio

PY - 2007/5/9

Y1 - 2007/5/9

N2 - We theoretically study transport properties of coupled quantum dots in parallel in the presence of electron-phonon (e-ph) interaction. Nonequilibrium transport under finite bias is calculated using the Keldysh Green function method. Firstly, we examine a double-dot interferometer with a penetrating magnetic flux (Aharonov-Bohm phase φ) between the two quantum dots. The differential conductance shows a sharp dip between double resonant peaks, as a function of energy levels in the quantum dots, when the two dots are equivalently coupled to external leads and 0 < φ < π. The e-ph interaction significantly decreases the dip, reflecting an emission of phonons from one of the quantum dots. This dephasing effect is more prominent under larger bias voltage. Secondly, we study a T-shaped double-dot system in which one of the dots is connected to the external leads (dot 1) and the other is disconnected (dot 2). The differential conductance shows a dip between two resonant peaks, as in the double-dot interferometer. The dip is weakly reduced by an emission of phonons from dot 2. Phonon emission from dot 1 does not result in dephasing and hence does not influence the dip. Therefore the dip of the conductance is more robust against the e-ph interaction in the T-shaped double-dot system than in the double-dot interferometer.

AB - We theoretically study transport properties of coupled quantum dots in parallel in the presence of electron-phonon (e-ph) interaction. Nonequilibrium transport under finite bias is calculated using the Keldysh Green function method. Firstly, we examine a double-dot interferometer with a penetrating magnetic flux (Aharonov-Bohm phase φ) between the two quantum dots. The differential conductance shows a sharp dip between double resonant peaks, as a function of energy levels in the quantum dots, when the two dots are equivalently coupled to external leads and 0 < φ < π. The e-ph interaction significantly decreases the dip, reflecting an emission of phonons from one of the quantum dots. This dephasing effect is more prominent under larger bias voltage. Secondly, we study a T-shaped double-dot system in which one of the dots is connected to the external leads (dot 1) and the other is disconnected (dot 2). The differential conductance shows a dip between two resonant peaks, as in the double-dot interferometer. The dip is weakly reduced by an emission of phonons from dot 2. Phonon emission from dot 1 does not result in dephasing and hence does not influence the dip. Therefore the dip of the conductance is more robust against the e-ph interaction in the T-shaped double-dot system than in the double-dot interferometer.

UR - http://www.scopus.com/inward/record.url?scp=34248381778&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=34248381778&partnerID=8YFLogxK

U2 - 10.1088/1367-2630/9/5/119

DO - 10.1088/1367-2630/9/5/119

M3 - Article

AN - SCOPUS:34248381778

VL - 9

JO - New Journal of Physics

JF - New Journal of Physics

SN - 1367-2630

M1 - 119

ER -