Magnetotransport in 3D Topological Insulator Nanowires

We investigate the transport characteristics of 3D topological insulator (3D TI) nanowires in external electric and magnetic fields. The wires host topologically nontrivial surface states wrapped around an insulating bulk and are modelled by surface effective Hamiltonians. A magnetic field along the wire axis leads to Aharonov-Bohm type oscillations of the conductance. Such oscillations have been observed in numerous systems and signal surface transport, though alone cannot prove its topological nature. Furthermore, it is not known how they are affected by the wire specific geometry which is never perfectly tubular as assumed in theoretical models up to now.
We thus focus on two issues:
(i) An accurate modelling of surface transport in gated, strained HgTe nanowires, accompanying experimental measurements performed by our collaborators (J. Ziegler & D. Weiss, University of Regensburg);
(ii) A theoretical study of magnetoconductance through shaped (tapered, curved) 3D TI nanowires. In particular, a non-constant radius along the wire direction gives rise to a spatial variation of the enclosed magnetic flux, implying novel quantum transport phenomena.