Quantum dot attached to superconducting leads: Relation between symmetric and asymmetric coupling
Result description
We study the Anderson single-level quantum dot attached to two BCS superconducting leads with the same gap size. We reveal that a system with asymmetric tunnel coupling to the leads (Gamma(L) not equal Gamma(R)) can be related to the symmetric system with the same net coupling strength Gamma=Gamma(L) + Gamma(R). Surprisingly, it is the symmetric case which is the most general, meaning that all physical quantities in the case of asymmetric coupling are fully determined by the symmetric ones. We give ready-to-use conversion formulas for the 0-pi phase transition boundary, on-dot quantities, and the Josephson current and illustrate them on the NRG results of Oguri, Tanaka and Bauer [Phys. Rev. B 87, 075432 (2013)] for the three-terminal setup. We apply our theory to the recent 0-p transition measurement of Delagrange et al. [Phys. Rev. B 93, 195437 (2016)] and determine the asymmetry of the experimental setup from the measured transition width. Finally, we establish that the widely assumed Kondo "universality" of physical quantities depending only on the ratio of the Kondo temperature and the superconducting gap T-K/Delta cannot hold for asymmetric junctions.
Keywords
devicesjunctionstransitiontransistorsimpuritysupercurrentjosephsoncarbon nanotubes
The result's identifiers
Result code in IS VaVaI
Result on the web
DOI - Digital Object Identifier
Alternative languages
Result language
angličtina
Original language name
Quantum dot attached to superconducting leads: Relation between symmetric and asymmetric coupling
Original language description
We study the Anderson single-level quantum dot attached to two BCS superconducting leads with the same gap size. We reveal that a system with asymmetric tunnel coupling to the leads (Gamma(L) not equal Gamma(R)) can be related to the symmetric system with the same net coupling strength Gamma=Gamma(L) + Gamma(R). Surprisingly, it is the symmetric case which is the most general, meaning that all physical quantities in the case of asymmetric coupling are fully determined by the symmetric ones. We give ready-to-use conversion formulas for the 0-pi phase transition boundary, on-dot quantities, and the Josephson current and illustrate them on the NRG results of Oguri, Tanaka and Bauer [Phys. Rev. B 87, 075432 (2013)] for the three-terminal setup. We apply our theory to the recent 0-p transition measurement of Delagrange et al. [Phys. Rev. B 93, 195437 (2016)] and determine the asymmetry of the experimental setup from the measured transition width. Finally, we establish that the widely assumed Kondo "universality" of physical quantities depending only on the ratio of the Kondo temperature and the superconducting gap T-K/Delta cannot hold for asymmetric junctions.
Czech name
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Czech description
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Classification
Type
Jimp - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10302 - Condensed matter physics (including formerly solid state physics, supercond.)
Result continuities
Project
GA16-19640S: Vibrational effects in nonequilibrium electronic transport through nanosystems
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)
Others
Publication year
2017
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Physical Review B
ISSN
2469-9950
e-ISSN
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Volume of the periodical
95
Issue of the periodical within the volume
19
Country of publishing house
US - UNITED STATES
Number of pages
9
Pages from-to
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UT code for WoS article
000401229000005
EID of the result in the Scopus database
2-s2.0-85023627284
Basic information
Result type
Jimp - Article in a specialist periodical, which is included in the Web of Science database
OECD FORD
Condensed matter physics (including formerly solid state physics, supercond.)
Year of implementation
2017