1999/12/06 by H. -P. Eckle, H. Johannesson, C. A. Stafford
Physics and Astronomy · #cond-mat.mes-hall
published as J. Low Temp. Phys. 118, 475 (2000) · To appear in the Proceedings from "Electron Transport in Mesoscopic Physics", J. Low Temp. Phys. (in press); 5 pages
arxiv created 1999/12/06 · arxiv updated 2009/11/30
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.