Dresden 2017 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 85: Topological Insulators III (joined session with TT)
HL 85.3: Vortrag
Freitag, 24. März 2017, 10:00–10:15, POT 251
Correlation and current anomalies in helical quantum dots — •Christophe De Beule1, Niccolò Traverso Ziani2, Mohammad Zarenia1, Bart Partoens1, and Björn Trauzettel2 — 1Department of Physics, University of Antwerp, 2020 Antwerp, Belgium — 2Institute of Theoretical Physics and Astrophysics, University of Würzburg, 97074 Würzburg, Germany
We investigate the ground-state properties of a quantum dot on the surface of a time-reversal invariant topological insulator. Confinement is realized by ferromagnetic barriers and Coulomb interaction is treated with exact diagonalization. The topological origin of the dot has several consequences: (i) spin polarization increases and the ground state exhibits quantum phase transitions as a function of interaction strength, (ii) the onset of Wigner correlations takes place mainly in one spin channel, and (iii) the ground state is characterized by a persistent current that changes direction as a function of the radius.
We also consider the effect of superconducting correlations on the properties of the quantum dot. This allows us to analyze the influence of perturbations that violate particle-number conservation on the formation of the Wigner molecule.