Magnetotransport of Dirac Fermions on the surface of a topological insulator

Abstract

We study the properties of Dirac fermions on the surface of a topological insulator in the presence of crossed electric and magnetic fields. We provide an exact solution to this problem and demonstrate that, in contrast to their counterparts in graphene, these Dirac fermions allow relative tuning of the orbital and Zeeman effects of an applied magnetic field by a crossed electric field along the surface. We also elaborate and extend our earlier results on normal metal-magnetic film-normal metal (NMN) and normal metal-barrier-magnetic film (NBM) junctions of topological insulators [Phys. Rev. Lett. {\bf 104}, 046403 (2010)]. For NMN junctions, we show that for Dirac fermions with Fermi velocity $v_F$, the transport can be controlled using the exchange field $\mathcal{J}$ of a ferromagnetic film over a region of width $d$. The conductance of such a junction changes from oscillatory to a monotonically decreasing function of $d$ beyond a critical $\mathcal{J}$ which leads to the possible realization of magnetic switches using these junctions. For NBM junctions with a potential barrier of width $d$ and potential $V_0$, we find that beyond a critical $\mathcal{J}$, the criteria of conductance maxima changes from $\chi =e{V}_{0}d/\hslash v_F=n\pi$ to $\chi =(n+1/2)\pi$ for integer $n$. Finally, we compute the subgap tunneling conductance of a normal metal-magnetic film-superconductor (NMS) junctions on the surface of a topological insulator and show that the position of the peaks of the zero-bias tunneling conductance can be tuned using the magnetization of the ferromagnetic film. We point out that these phenomena have no analogs in either conventional two-dimensional materials or Dirac electrons in graphene and suggest experiments to test our theory.

11 pages, 12 figures; v1

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• Junction between surfaces of two topological insulators
• Photon dressed electronic states in topological insulators: Tunneling and conductance
• The topological surface state of $\alpha$-Sn on InSb(001) as studied by photoemission
• Spin-polarized tunneling current through a thin film of topological insulator in a parallel magnetic field
• Electromagnetic spin polarization on the surface of topological insulator
• Giant magnetoresistance in the junction of two ferromagnets on the surface of diffusive topological insulators
• Dynamics of the (spin-) Hall effect in topological insulators and graphene
• Edge states of a three-dimensional topological insulator
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• Anisotropic transport of normal metal-barrier-normal metal junctions in monolayer phosphorene
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• Optically tunable spin transport on the surface of a topological insulator
• Transport across junctions of a Weyl and a multi-Weyl semimetal
• Spin-charge transport driven by magnetization dynamics on disordered surface of doped topological insulators
• Skyrmion-induced bound states on the surface of 3D Topological Insulators
• Spin polarized STM spectra of Dirac Fermions on the surface of a topological insulator
• Transport across junctions of pseudospin-one fermions
• Confining electrons on a topological insulator surface using potentials and a magnetic field
• Adiabatic quantum pumping through surface states in 3D topological insulators
• Spin Transport and Accumulation in 2D Weyl Fermion System
• Transport in a thin topological insulator with potential and magnetic barriers
• Transport on a topological insulator surface with a time-dependent magnetic barrier
• The stability of the fractional quantum Hall effect in topological insulators
• Electric and thermoelectric transport in graphene and helical metal in finite magnetic fields
• Theory of universal differential conductance of magnetic Weyl type -II junctions
• A Green's function approach to Topological Insulator junctions with magnetic and superconducting regions
• Effect of inplane electric field on magnetotransport in helical metal
• A semi-classical analysis of Dirac fermions in 2+1 dimensions