Poor Man's Scaling and Green Function Analysis of the Kondo Anomaly in Single-Level Quantum Dots

M. Wawrzyniak a, R. Świrkowicz b, M. Wilczyński b, J. Barnaś a,c a Department of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland b Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw, Poland c Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Poznań, Poland

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Received: 9 07 2007;

Kondo effect in a single-level quantum dot attached to magnetic leads is studied theoretically by the "poor man's scaling" and non-equilibrium Green function methods. From the scaling equations we derive the Kondo temperature as a function of the model parameters - in particular as a function of the angle between magnetic moments. Transport characteristics, i.e. differential conductance and tunnel magnetoresistance associated with magnetization rotation, were calculated within the non-equilibrium Green function formalism based on the equation of motion method.

DOI: 10.12693/APhysPolA.113.553 PACS numbers: 75.20.Hr, 72.15.Qm, 72.25.-b, 73.23.Hk