Dresden 2009 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 11: Transport: Nanoelectronics I - Quantum Dots and Wires, Point Contacts 2

TT 11.10: Vortrag

Montag, 23. März 2009, 16:30–16:45, HSZ 301

Magnetic field dependence of 0.7 Anomaly in Quantum Point Contacts: A Study Using the Functional Renormalization Group — •Florian Bauer and Jan von Delft — Arnold Sommerfeld Center for Theoretical Physics, Munich

We study the magnetic field dependence of the 0.7 anomaly of the conductance through a quantum point contact at zero temperature, using the functional renormalization group (fRG). We model a 1-D quantum wire using a tight-binding chain with short-ranged Coulomb interactions and a prescribed onsite potential to mimick the potential barrier caused by the 2-D constriction. Our fRG results qualitatively reproduce the experimentally observed magnetic field dependence of the conductance anomaly (splitting of the first conductance step into two substeps) and the shot noise. The resulting effective g-factor is strongly enhanced by interactions, in agreement with the experimental observation of anomalously large g factors.