Spin-symmetric solution of an interacting quantum dot attached to superconducting leads: Andreev states and the 0-pi transition
Result description
Behavior of Andreev gap states in a quantum dot with Coulomb repulsion symmetrically attached to superconducting leads is studied via the perturbation expansion in the interaction strength. We find the exact asymptotic form of the spin-symmetric solution for the Andreev states continuously approaching the Fermi level. We thereby derive a critical interaction at which the Andreev states at zero temperature merge at the Fermi energy, being the upper bound for the 0-pi transition. We show that the spin-symmetric solution becomes degenerate beyond this interaction, in the pi phase, and the Andreev states do not split unless the degeneracy is lifted. We further demonstrate that the degeneracy of the spin-symmetric state extends also into the 0 phase in which the solutions with zero and non-zero frequencies of the Andreev states may coexist.
Keywords
mesoscopic and nanoscale systemsAndreev bound states0-pi transitionperturbation theory
The result's identifiers
Result code in IS VaVaI
Alternative codes found
RIV/00216208:11320/16:10327268
Result on the web
DOI - Digital Object Identifier
Alternative languages
Result language
angličtina
Original language name
Spin-symmetric solution of an interacting quantum dot attached to superconducting leads: Andreev states and the 0-pi transition
Original language description
Behavior of Andreev gap states in a quantum dot with Coulomb repulsion symmetrically attached to superconducting leads is studied via the perturbation expansion in the interaction strength. We find the exact asymptotic form of the spin-symmetric solution for the Andreev states continuously approaching the Fermi level. We thereby derive a critical interaction at which the Andreev states at zero temperature merge at the Fermi energy, being the upper bound for the 0-pi transition. We show that the spin-symmetric solution becomes degenerate beyond this interaction, in the pi phase, and the Andreev states do not split unless the degeneracy is lifted. We further demonstrate that the degeneracy of the spin-symmetric state extends also into the 0 phase in which the solutions with zero and non-zero frequencies of the Andreev states may coexist.
Czech name
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Czech description
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Classification
Type
Jx - Unclassified - Peer-reviewed scientific article (Jimp, Jsc and Jost)
CEP classification
BM - Solid-state physics and magnetism
OECD FORD branch
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Result continuities
Project
Continuities
I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace
Others
Publication year
2016
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
European Physical Journal B
ISSN
1434-6028
e-ISSN
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Volume of the periodical
89
Issue of the periodical within the volume
9
Country of publishing house
DE - GERMANY
Number of pages
12
Pages from-to
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UT code for WoS article
000383156000001
EID of the result in the Scopus database
2-s2.0-84987932319
Basic information
Result type
Jx - Unclassified - Peer-reviewed scientific article (Jimp, Jsc and Jost)
CEP
BM - Solid-state physics and magnetism
Year of implementation
2016