Eur. Phys. J. B (2015) 88: 111
https://doi.org/10.1140/epjb/e2015-60029-2

Regular Article

Scaling analysis for Aharonov-Bohm ring with an embedded quantum dot connected with ferromagnetic leads

Department of Complex and Intelligent Systems, School of Systems Information Science, Future University Hakodate, 041-8655 Hakodate, Japan

^a e-mail: satoshi@fun.ac.jp

Received: 12 January 2015
Received in final form: 17 March 2015
Published online: 4 May 2015

Abstract

In this study, we consider the Kondo temperature and differential conductance for an Aharonov-Bohm ring with an embedded quantum dot connected with noncollinear ferromagnetic leads. Starting from the tight-binding model, we propose an equivalent Anderson model, in which the density of states depends on the Aharonov-Bohm phase. By applying the poor man’s scaling approach to the Hamiltonian, we derive the dependences of the Kondo temperature and differential conductance on the Aharonov-Bohm phase, spin polarization, angle of magnetic moment, and asymmetry parameters. We show conditions for the nonmonotonic behavior of the differential conductance in terms of the spin splitting and Aharonov-Bohm phase. In addition, by extending the model to the case of a finite ring size, we show that the Kondo temperature crucially depends on ring size, but the properties of the scaled temperature are similar to ones for the small ring-size limit.