### Abstract

We study the influence of a magnetic impurity or ultrasmall quantum dot on the charge persistent current of a mesoscopic ring. The system consists of electrons in a one-dimensional ring threaded by spin-dependent Aharonov-Bohm/Casher fluxes, coupled via an antiferromagnetic exchange interaction to a localized electron. By passing to a basis of electron states with definite parities, the problem is mapped onto a Kondo model for the even-parity channel plus free electrons in the odd-parity channel. The twisted boundary conditions representing the fluxes couple states of opposite parity unless the twist angles satisfy φ_{α} = f_{α}π, where fα are integers, with spin index α = ↑, ↓. For these special values of φ_{α}, the model is solved exactly by a Bethe ansatz. Special cases are investigated in detail. In particular we show that the charge stiffness in the case φ_{↑} = φ_{↓} is insensitive to the presence of the magnetic impurity/quantum dot.

Original language | English (US) |
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Pages (from-to) | 475-483 |

Number of pages | 9 |

Journal | Journal of Low Temperature Physics |

Volume | 118 |

Issue number | 5-6 |

State | Published - 2000 |

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### ASJC Scopus subject areas

- Physics and Astronomy (miscellaneous)

### Cite this

*Journal of Low Temperature Physics*,

*118*(5-6), 475-483.

**Kondo Impurity in a Mesoscopic Ring : Charge Persistent Current.** / Eckle, H. P.; Johannesson, H.; Stafford, Charles A.

Research output: Contribution to journal › Article

*Journal of Low Temperature Physics*, vol. 118, no. 5-6, pp. 475-483.

}

TY - JOUR

T1 - Kondo Impurity in a Mesoscopic Ring

T2 - Charge Persistent Current

AU - Eckle, H. P.

AU - Johannesson, H.

AU - Stafford, Charles A

PY - 2000

Y1 - 2000

N2 - We study the influence of a magnetic impurity or ultrasmall quantum dot on the charge persistent current of a mesoscopic ring. The system consists of electrons in a one-dimensional ring threaded by spin-dependent Aharonov-Bohm/Casher fluxes, coupled via an antiferromagnetic exchange interaction to a localized electron. By passing to a basis of electron states with definite parities, the problem is mapped onto a Kondo model for the even-parity channel plus free electrons in the odd-parity channel. The twisted boundary conditions representing the fluxes couple states of opposite parity unless the twist angles satisfy φα = fαπ, where fα are integers, with spin index α = ↑, ↓. For these special values of φα, the model is solved exactly by a Bethe ansatz. Special cases are investigated in detail. In particular we show that the charge stiffness in the case φ↑ = φ↓ is insensitive to the presence of the magnetic impurity/quantum dot.

AB - We study the influence of a magnetic impurity or ultrasmall quantum dot on the charge persistent current of a mesoscopic ring. The system consists of electrons in a one-dimensional ring threaded by spin-dependent Aharonov-Bohm/Casher fluxes, coupled via an antiferromagnetic exchange interaction to a localized electron. By passing to a basis of electron states with definite parities, the problem is mapped onto a Kondo model for the even-parity channel plus free electrons in the odd-parity channel. The twisted boundary conditions representing the fluxes couple states of opposite parity unless the twist angles satisfy φα = fαπ, where fα are integers, with spin index α = ↑, ↓. For these special values of φα, the model is solved exactly by a Bethe ansatz. Special cases are investigated in detail. In particular we show that the charge stiffness in the case φ↑ = φ↓ is insensitive to the presence of the magnetic impurity/quantum dot.

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M3 - Article

VL - 118

SP - 475

EP - 483

JO - Journal of Low Temperature Physics

JF - Journal of Low Temperature Physics

SN - 0022-2291

IS - 5-6

ER -