Dresden 2014 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 21: Transport: Quantum Dots, Quantum Wires, Point Contacts II (TT jointly with O)
O 21.3: Vortrag
Montag, 31. März 2014, 16:30–16:45, HSZ 204
Interplay of edge state polarization and a Zeeman split quantum dot — •Benedikt Probst1, Pauli Virtanen2, and Patrik Recher1 — 1Institute for Mathematical Physics, TU Braunschweig, Braunschweig, Germany — 2O.V. Lounasmaa Laboratory, Aalto University, Finland
Topological insulators are a novel state of matter showing interesting physics. One of the effects realized in these materials is the quantum spin Hall effect in which electrons with different spin propagate in different directions on the edge of the system. Applying a bias to the system therefore leads to a spin bias for the edge state. We consider a system in which a quantum dot in the Coulomb blockade regime is attached to a helical Luttinger liquid. This quantum dot is treated as a localized spin, which can be manipulated by a magnetic field. The dynamics of the dots are described by setting up a general master equation. From the steady state of the system the polarization of the dot and the differential edge conductance is calculated. We discuss a regime in which the dot polarization exhibits a strong bias dependence and a regime in which the transport shows a characteristic bias asymmetry which allows to identify the relative orientation of the spin polarization in the edge state with respect to the magnetic field.