Berlin 2015 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 20: POSTER Ib

MA 20.40: Poster

Dienstag, 17. März 2015, 09:30–13:00, Poster A

The tunnel magnetoresistance and shot noise of triple quantum dots in the sequential and cotunneling regimes — •Kacper Wrześniewski and Ireneusz Weymann — Faculty of Physics, Adam Mickiewicz University in Poznań, ul. Umultowska 85, 61-614 Poznań, Poland

We study the spin-dependent transport through a coherent triple quantum dot system weakly coupled to external ferromagnetic electrodes. The calculations are performed with the aid of the real-time diagrammatic technique up to the second order of the perturbation theory with respect to the coupling to the leads. We discuss the behavior of the current, tunnel magnetoresistance and shot noise in both the linear and nonlinear response, focusing on the role of cotunneling processes. It is shown that, depending on the device geometry, parameters of the model and applied voltages, the system can exhibit negative tunnel magnetoresistance, negative differential conductance and super-Poissonian shot noise. The mechanisms leading to the above effects are thoroughly analyzed.