Quantum interference in transport through almost symmetric double quantum dots
(2019) In Physical Review B 99(12).- Abstract
We theoretically investigate transport signatures of quantum interference in highly symmetric double quantum dots in a parallel geometry and demonstrate that extremely weak symmetry-breaking effects can have a dramatic influence on the current. Our calculations are based on a master equation in which quantum interference enters as nondiagonal elements of the density matrix of the double quantum dots. We also show that many results have a physically intuitive meaning when recasting our equations as Bloch-like equations for a pseudospin associated with the dot occupation. In the perfectly symmetric configuration with equal tunnel couplings and orbital energies of both dots, there is no unique stationary-state density matrix.... (More)
We theoretically investigate transport signatures of quantum interference in highly symmetric double quantum dots in a parallel geometry and demonstrate that extremely weak symmetry-breaking effects can have a dramatic influence on the current. Our calculations are based on a master equation in which quantum interference enters as nondiagonal elements of the density matrix of the double quantum dots. We also show that many results have a physically intuitive meaning when recasting our equations as Bloch-like equations for a pseudospin associated with the dot occupation. In the perfectly symmetric configuration with equal tunnel couplings and orbital energies of both dots, there is no unique stationary-state density matrix. Interestingly, however, adding arbitrarily small symmetry-breaking terms to the tunnel couplings or orbital energies stabilizes a stationary state either with or without quantum interference, depending on the competition between these two perturbations. The different solutions can correspond to very different current levels. Therefore, if the orbital energies and/or tunnel couplings are controlled by, e.g., electrostatic gating, the double quantum dot can act as an exceptionally sensitive electric switch.
(Less)
- author
- Li, Zeng Zhao LU and Leijnse, Martin LU
- organization
- publishing date
- 2019
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Physical Review B
- volume
- 99
- issue
- 12
- article number
- 125406
- publisher
- American Physical Society
- external identifiers
-
- scopus:85062717443
- ISSN
- 2469-9950
- DOI
- 10.1103/PhysRevB.99.125406
- language
- English
- LU publication?
- yes
- id
- 9b4615f3-26c1-4134-aa54-bd6881ca05c3
- date added to LUP
- 2019-03-19 13:00:28
- date last changed
- 2025-04-04 15:18:00
@article{9b4615f3-26c1-4134-aa54-bd6881ca05c3,
abstract = {{<p>We theoretically investigate transport signatures of quantum interference in highly symmetric double quantum dots in a parallel geometry and demonstrate that extremely weak symmetry-breaking effects can have a dramatic influence on the current. Our calculations are based on a master equation in which quantum interference enters as nondiagonal elements of the density matrix of the double quantum dots. We also show that many results have a physically intuitive meaning when recasting our equations as Bloch-like equations for a pseudospin associated with the dot occupation. In the perfectly symmetric configuration with equal tunnel couplings and orbital energies of both dots, there is no unique stationary-state density matrix. Interestingly, however, adding arbitrarily small symmetry-breaking terms to the tunnel couplings or orbital energies stabilizes a stationary state either with or without quantum interference, depending on the competition between these two perturbations. The different solutions can correspond to very different current levels. Therefore, if the orbital energies and/or tunnel couplings are controlled by, e.g., electrostatic gating, the double quantum dot can act as an exceptionally sensitive electric switch.</p>}},
author = {{Li, Zeng Zhao and Leijnse, Martin}},
issn = {{2469-9950}},
language = {{eng}},
number = {{12}},
publisher = {{American Physical Society}},
series = {{Physical Review B}},
title = {{Quantum interference in transport through almost symmetric double quantum dots}},
url = {{http://dx.doi.org/10.1103/PhysRevB.99.125406}},
doi = {{10.1103/PhysRevB.99.125406}},
volume = {{99}},
year = {{2019}},
}