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TT: Fachverband Tiefe Temperaturen

TT 1: Topological Insulators 1 (joint session TT/HL)

TT 1.7: Vortrag

Montag, 16. März 2020, 11:00–11:15, HSZ 03

Magnetoconductance, Quantum Hall Effect, and Coulomb Blockade in Topological Insulator Nanowires — •Raphael Kozlovsky, Ansgar Graf, Denis Kochan, Klaus Richter, and Cosimo Gorini — Institut für Theoretische Physik, Universität Regensburg, 93040 Regensburg, Germany

Three-dimensional topological insulator (3DTI) nanowires host topologically non-trivial surface states wrapped around an insulating bulk. We investigate the transport properties of such wires subject to external electric and magnetic fields using effective surface Dirac Hamiltonians. By considering shaped (tapered, curved) 3DTI nanowires, we go beyond the well-studied cylindrical geometry [1] and thereby access intriguing mesoscopic transport phenomena: While the conductance of a wire in perpendicular magnetic field is in general quantized due to higher-order topological hinge states, the conductance in longitudinal magnetic field depends on the precise wire geometry. For rotationally symmetric nanowires with varying radius, a coaxial magnetic field leads to a spatial variation of the enclosed magnetic flux giving rise to a non-trivial mass potential along the wire direction. Depending on the radial profile of the wire, this mass potential leads, for instance, to a conductance governed by the transmission through Dirac Landau levels, or to Coulomb blockade.

[1] arxiv:1909.13124 (2019)