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 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.
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 |
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Materials Science(all)
- Condensed Matter Physics