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Transient dynamics of a magnetic impurity coupled to superconducting electrodes : Exact numerics versus perturbation theory

Seoane Souto, R. LU orcid ; Feiguin, A. E. ; Martín-Rodero, A. and Yeyati, A. Levy (2021) In Physical Review B 104(21).
Abstract

Impurities coupled to superconductors offer a controlled platform to understand the interplay between superconductivity, many-body interactions, and nonequilibrium physics. In the equilibrium situation, local interactions at the impurity induce a transition from the spin-singlet to the spin-doublet ground state, resulting in a supercurrent sign reversal (0-π transition). In this work, we apply the exact time-dependent density matrix renormalization group method to simulate the transient dynamics of such superconducting systems. We also use a perturbative approximation to analyze their properties at longer times. These two methods agree for a wide range of parameters. In a phase-biased situation, the system gets trapped in a metastable... (More)

Impurities coupled to superconductors offer a controlled platform to understand the interplay between superconductivity, many-body interactions, and nonequilibrium physics. In the equilibrium situation, local interactions at the impurity induce a transition from the spin-singlet to the spin-doublet ground state, resulting in a supercurrent sign reversal (0-π transition). In this work, we apply the exact time-dependent density matrix renormalization group method to simulate the transient dynamics of such superconducting systems. We also use a perturbative approximation to analyze their properties at longer times. These two methods agree for a wide range of parameters. In a phase-biased situation, the system gets trapped in a metastable state characterized by a lower supercurrent compared to the equilibrium case. We show that local Coulomb interactions do not provide an effective relaxation mechanism for the initially trapped quasiparticles. In contrast, other relaxation mechanisms, such as coupling to a third normal lead, make the impurity spin relax for parameter values corresponding to the equilibrium 0 phase. For parameters corresponding to the equilibrium π phase the impurity converges to a spin-polarized stationary state. Similar qualitative behavior is found for a voltage-biased junction, which provides an effective relaxation mechanism for the trapped quasiparticles in the junction.

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author
; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Review B
volume
104
issue
21
article number
214506
publisher
American Physical Society
external identifiers
  • scopus:85121698056
ISSN
2469-9950
DOI
10.1103/PhysRevB.104.214506
language
English
LU publication?
yes
additional info
Publisher Copyright: © Published by the American Physical Society
id
9a2e7841-cabb-4eb6-919c-50ab0c460238
date added to LUP
2022-01-28 09:52:29
date last changed
2023-11-09 03:52:48
@article{9a2e7841-cabb-4eb6-919c-50ab0c460238,
  abstract     = {{<p>Impurities coupled to superconductors offer a controlled platform to understand the interplay between superconductivity, many-body interactions, and nonequilibrium physics. In the equilibrium situation, local interactions at the impurity induce a transition from the spin-singlet to the spin-doublet ground state, resulting in a supercurrent sign reversal (0-π transition). In this work, we apply the exact time-dependent density matrix renormalization group method to simulate the transient dynamics of such superconducting systems. We also use a perturbative approximation to analyze their properties at longer times. These two methods agree for a wide range of parameters. In a phase-biased situation, the system gets trapped in a metastable state characterized by a lower supercurrent compared to the equilibrium case. We show that local Coulomb interactions do not provide an effective relaxation mechanism for the initially trapped quasiparticles. In contrast, other relaxation mechanisms, such as coupling to a third normal lead, make the impurity spin relax for parameter values corresponding to the equilibrium 0 phase. For parameters corresponding to the equilibrium π phase the impurity converges to a spin-polarized stationary state. Similar qualitative behavior is found for a voltage-biased junction, which provides an effective relaxation mechanism for the trapped quasiparticles in the junction.</p>}},
  author       = {{Seoane Souto, R. and Feiguin, A. E. and Martín-Rodero, A. and Yeyati, A. Levy}},
  issn         = {{2469-9950}},
  language     = {{eng}},
  month        = {{12}},
  number       = {{21}},
  publisher    = {{American Physical Society}},
  series       = {{Physical Review B}},
  title        = {{Transient dynamics of a magnetic impurity coupled to superconducting electrodes : Exact numerics versus perturbation theory}},
  url          = {{http://dx.doi.org/10.1103/PhysRevB.104.214506}},
  doi          = {{10.1103/PhysRevB.104.214506}},
  volume       = {{104}},
  year         = {{2021}},
}