Regensburg 2019 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 3: Topological Insulators (joint session TT/MA)

TT 3.10: Talk

Monday, April 1, 2019, 12:00–12:15, Theater

Coulomb Blockade in Topological Insulator Quantum Dots — Klaus Richter, Cosimo Gorini, Raphael Kozlovsky, •Ansgar Graf, and Andreas Hackl — Universität Regensburg, Institut für Theoretische Physik, 93053 Regensburg

Three-dimensional topological insulator (3DTI) nanowires host topologically non-trivial surface states wrapped around an insulating bulk. We model these states by two-dimensional effective Dirac Hamiltonians. A coaxial magnetic field is known to produce Aharonov-Bohm (AB) type oscillations in the conductance. The corresponding AB phase and a Berry phase originating from spin-momentum locking affect the angular momentum wave number. We investigate 3DTI nanowires where additionally the longitudinal wave number gets quantized by size confinement, such that a '3DTI quantum dot' exhibiting a fully discrete energy spectrum is obtained. Such confinement is not possible by electrostatic means (Klein tunneling) but can be achieved via the interplay between non-trivial geometry (shaped nanowire) and a homogeneous coaxial magnetic field. We are looking for signatures of Berry phase and Dirac states in the single-electron transport regime (in particular in the Coulomb diamonds) of such a 3DTI quantum dot.