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Kondo Impurity in a Mesoscopic Ring: Charge Persistent Current

H. -P. Eckle·H. Johannesson·C. A. Stafford
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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. States of opposite parities decouple for values of the flux corresponding to periodic or antiperiodic boundary conditions. For these special cases, the model is solved exactly by a Bethe ansatz, allowing for an exact calculation of the charge persistent current. In particular we show that the charge stiffness in the special case of spin-independent fluxes is insensitive to the presence of the magnetic impurity/quantum dot.

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H. -P. Eckle, H. Johannesson, C. A. Stafford. 1999-12-06. Kondo Impurity in a Mesoscopic Ring: Charge Persistent Current. https://arxiv.org/abs/cond-mat/9912093

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