Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:cond-mat/0007414

Dephasing of Aharonov-Bohm oscillations in a mesoscopic ring with a magnetic impurity

Sandeep Joshi, Debendranath Sahoo, A. M. Jayannavar

Published Jul 26, 2000• 0 citations
arXivHTMLPDF

Abstract

We present a detailed analysis of the Aharonov-Bohm interference oscillations manifested through transmission of an electron in a mesoscopic ring with a magnetic impurity atom inserted in one of its arms. The electron interacts with the impurity through the exchange interaction leading to exchange spin-flip scattering. Transmission in the spin-flipped and spin-unflipped channels are explicitly calculated. We show that the spin-flipper acts as a dephasor in spite of absence of any inelastic scattering. The spin-conductance (related to spin-polarized transmission coefficient) is asymmetric in the flux reversal as opposed to the two probe conductance which is symmetric under flux reversal.

DOI
10.48550/arxiv.cond-mat/0007414

Related papers

Spin-polarized transport through a double Aharonov–Bohm ring in the presence of magnetic impurity

Gao Ying‐Fang, Yongping Zhang, Liang Jiu-Qing

The Aharonov–Bohm (AB) interference oscillations manifested through transmission of an electron in a mesoscopic device with a double-ring in the presence of a magnetic impurity serving as the spin-flipper are studied. The spin-flipper is demonstrated to indeed cause the partial decoherence of the AB interference. Moreover, it is found that the spin-up/down transmission coefficients are asymmetric in the flux reversal while the reflection coefficients as well as that the total transmission coefficient are symmetric.

Chinese Physics•Dec 23, 2004•8 citations

Loss of interference in an Aharonov-Bohm ring

Sandeep Joshi, Debendranath Sahoo, Jayannavar, A. M.

We study a simple model of dephasing of Aharonov-Bohm oscillations in the transmission of an electron across a mesoscopic ring. A magnetic impurity in one of the arms of the ring couples to the electron spin via an exchange interaction. This interaction leads to spin flip scattering and induces dephasing via entanglement. This is akin to the models evoked earlier to explain destruction of interference due to which-path information in double-slit experiments. Total transmission is found to be symmetric under flux reversal but not the spin polarization.

arXiv:cond-mat/0101436•Jan 29, 2001•1 citation

ROLE OF QUANTUM ENTANGLEMENT DUE TO A MAGNETIC IMPURITY ON CURRENT MAGNIFICATION EFFECT IN MESOSCOPIC OPEN RINGS

Colin Benjamin, Sandeep Joshi, Debendranath Sahoo +1 more

We study the current magnification effect in presence of exchange scattering of electron from a magnetic impurity placed in one arm of an open mesoscopic ring. The exchange interaction causes entanglement of electron spin and impurity spin. Earlier studies have shown that such an entanglement causes reduction or loss of interference in the Aharonov–Bohm oscillations leading to decoherence. We find however, that this entanglement, in contradiction to the naive expectation of a reduction in current magnification leads to enhancement as well as suppression of the effect. We also observe additional novel features like new resonances and current reversals.

arXiv:cond-mat/0011402•Modern Physics Letters B•Jan 15, 2001•12 citations

Entanglement-induced electron coherence in a mesoscopic ring with two magnetic impurities

Francesco Ciccarello, G. Massimo Palma, Michelangelo Zarcone

We investigate the Aharonov-Bohm (AB) interference pattern in the electron transmission through a mesoscopic ring in which two identical noninteracting magnetic impurities are embedded. Adopting a quantum waveguide theory, we derive the exact transmission probability amplitudes and study the influence of maximally entangled states of the impurity spins on the electron transmittivity interference pattern. For suitable electron wave vectors, we show that the amplitude of AB oscillations in the absence of impurities is, in fact, not reduced within a wide range of the electron-impurity coupling constant when the maximally entangled singlet state is prepared. Such state is thus able to inhibit the usual electron decoherence due to scattering by magnetic impurities. We also show how this maximally entangled state of the impurity spins can be generated via electron scattering.

arXiv:cond-mat/0612057•Physical Review B•May 10, 2007•22 citations

Microscopic mechanisms of dephasing due to electron-electron interactions

Rok Žitko, J. Bonča

We develop a nonperturbative numerical method to study tunneling of a single electron through an Aharonov-Bohm ring where several strongly interacting electrons are bound. Inelastic processes and spin-flip scattering are taken into account. The method is applied to study microscopic mechanisms of dephasing in a nontrivial model. We show that the electron-electron interactions described by the Hubbard Hamiltonian lead to strong dephasing: the transmission probability at flux $\ensuremath{\Phi}=\ensuremath{\pi}$ is high even at small interaction strength. In addition to inelastic scattering, we identify two energy-conserving mechanisms of dephasing: symmetry-changing and spin-flip scattering. The many-electron state on the ring determines which of these mechanisms will be at play: transmitted current can occur either in elastic or inelastic channels, with or without changing the spin of the scattering electron.

arXiv:cond-mat/0305335•Physical review. B, Condensed matter•Aug 13, 2003•10 citations

Electron spin transport through an Aharonov–Bohm ring—a spin switch

Chenglong Jia, Shun-Jin Wang, Hong‐Gang Luo +1 more

Electron spin transport through an Aharonov–Bohm ring driven by time-dependent inhomogeneous magnetic fields is treated. The system possesses an su (2) l × su (2) s dynamical symmetry in both orbital angular momentum space and spin space, and is thus proved to be integrable according to algebraic dynamics. Based on the analytical solutions, the relevant physical quantities such as electric current, spin current, magnetization and conductance are calculated. It is found that for a magnetic field with π/2 twist angle, the direction of spin-polarization will be reversed at zero magnetic flux. In the resonant rotating magnetic field, the spin transmission is oscillating with time t , and can reach unity, so that a complete spin flip can also be induced. The results obtained may be of practical significance for the design of nano-electromagnetic spin devices, such as a spin switch, in a controllable way.

Journal of Physics Condensed Matter•Mar 12, 2004•3 citations
We present a detailed analysis of the Aharonov-Bohm interference oscillations manifested through transmission of an electron in a mesoscopic ring with a magnetic impurity atom inserted in one of its arms. The electron interacts with the impurity through the exchange interaction leading to exchange spin-flip scattering. Transmission in the spin-flipped and spin-unflipped channels are explicitly calculated. We show that the spin-flipper acts as a dephasor in spite of absence of any inelastic scattering. The spin-conductance (related to spin-polarized transmission coefficient) is asymmetric in the flux reversal as opposed to the two probe conductance which is symmetric under flux reversal.
The Aharonov–Bohm (AB) interference oscillations manifested through transmission of an electron in a mesoscopic device with a double-ring in the presence of a magnetic impurity serving as the spin-flipper are studied. The spin-flipper is demonstrated to indeed cause the partial decoherence of the AB interference. Moreover, it is found that the spin-up/down transmission coefficients are asymmetric in the flux reversal while the reflection coefficients as well as that the total transmission coefficient are symmetric.
We study a simple model of dephasing of Aharonov-Bohm oscillations in the transmission of an electron across a mesoscopic ring. A magnetic impurity in one of the arms of the ring couples to the electron spin via an exchange interaction. This interaction leads to spin flip scattering and induces dephasing via entanglement. This is akin to the models evoked earlier to explain destruction of interference due to which-path information in double-slit experiments. Total transmission is found to be symmetric under flux reversal but not the spin polarization.
We study the current magnification effect in presence of exchange scattering of electron from a magnetic impurity placed in one arm of an open mesoscopic ring. The exchange interaction causes entanglement of electron spin and impurity spin. Earlier studies have shown that such an entanglement causes reduction or loss of interference in the Aharonov–Bohm oscillations leading to decoherence. We find however, that this entanglement, in contradiction to the naive expectation of a reduction in current magnification leads to enhancement as well as suppression of the effect. We also observe additional novel features like new resonances and current reversals.
We investigate the Aharonov-Bohm (AB) interference pattern in the electron transmission through a mesoscopic ring in which two identical noninteracting magnetic impurities are embedded. Adopting a quantum waveguide theory, we derive the exact transmission probability amplitudes and study the influence of maximally entangled states of the impurity spins on the electron transmittivity interference pattern. For suitable electron wave vectors, we show that the amplitude of AB oscillations in the absence of impurities is, in fact, not reduced within a wide range of the electron-impurity coupling constant when the maximally entangled singlet state is prepared. Such state is thus able to inhibit the usual electron decoherence due to scattering by magnetic impurities. We also show how this maximally entangled state of the impurity spins can be generated via electron scattering.
We develop a nonperturbative numerical method to study tunneling of a single electron through an Aharonov-Bohm ring where several strongly interacting electrons are bound. Inelastic processes and spin-flip scattering are taken into account. The method is applied to study microscopic mechanisms of dephasing in a nontrivial model. We show that the electron-electron interactions described by the Hubbard Hamiltonian lead to strong dephasing: the transmission probability at flux $\ensuremath{\Phi}=\ensuremath{\pi}$ is high even at small interaction strength. In addition to inelastic scattering, we identify two energy-conserving mechanisms of dephasing: symmetry-changing and spin-flip scattering. The many-electron state on the ring determines which of these mechanisms will be at play: transmitted current can occur either in elastic or inelastic channels, with or without changing the spin of the scattering electron.
Electron spin transport through an Aharonov–Bohm ring driven by time-dependent inhomogeneous magnetic fields is treated. The system possesses an su (2) l × su (2) s dynamical symmetry in both orbital angular momentum space and spin space, and is thus proved to be integrable according to algebraic dynamics. Based on the analytical solutions, the relevant physical quantities such as electric current, spin current, magnetization and conductance are calculated. It is found that for a magnetic field with π/2 twist angle, the direction of spin-polarization will be reversed at zero magnetic flux. In the resonant rotating magnetic field, the spin transmission is oscillating with time t , and can reach unity, so that a complete spin flip can also be induced. The results obtained may be of practical significance for the design of nano-electromagnetic spin devices, such as a spin switch, in a controllable way.