Transport in Selectively Magnetically Doped Topological Insulator Wires

Abstract

We study the electronic and transport properties of a topological insulator nanowire including selective magnetic doping of its surfaces. We use a model which is appropriate to describe materials like Bi${}_2$Se${}_3$ within a k.p approximation and consider nanowires with a rectangular geometry. Within this model the magnetic doping at the (111) surfaces induces a Zeeman field which opens a gap at the Dirac cones corresponding to the surface states. For obtaining the transport properties in a two terminal configuration we use a recursive Green function method based on a tight-binding model which is obtained by discretizing the original continuous model. For the case of uniform magnetization of two opposite nanowire (111) surfaces we show that the conductance can switch from a quantized value of $e^2/h$ (when the magnetizations are equal) to a very small value (when they are opposite). We also analyze the case of non-uniform magnetizations in which the Zeeman field on the two opposite surfaces change sign at the middle of the wire. For this case we find that conduction by resonant tunneling through a chiral state bound at the middle of the wire is possible. The resonant level position can be tuned by imposing an Aharonov-Bohm flux through the nanowire cross section.

8 pages, 7 figures

References in corpus (8)

• Discovery (theoretical prediction and experimental observation) of a large-gap topological-insulator class with spin-polarized single-Dirac-cone on the surface
• Topological confinement in bilayer graphene
• Conductance quantization and snake states in graphene magnetic waveguides
• Non-local transport via edge-states in InAs/GaSb coupled quantum wells
• Magnetic proximity effect at Bi${}_2$Se${}_3$/EuS interface with broken inversion symmetry
• Resolving the Dirac Cone on the Surface of Bi2Te3 Topological Insulator Nanowires by Field-Effect Measurements
• Topological Effects on the Magnetoconductivity in Topological Insulators
• Suppression of Conductance in a Topological Insulator Nanostep Junction

Cited by in corpus (5)

• Quantum Hall Edge States in Topological Insulator Nanoribbons
• Chiral interface states in graphene $p$-$n$ junctions
• Proximity induced time-reversal topological superconductivity in Bi2Se3 films without phase tuning
• A Green's function approach to Topological Insulator junctions with magnetic and superconducting regions
• Confinement versus interface bound states in spin-orbit coupled nanowires