Mondal, S. ; Sen, D. ; Sengupta, K. ; Shankar, R. (2010) Magnetotransport of Dirac fermions on the surface of a topological insulator Physical Review B: Condensed Matter and Materials Physics, 82 (4). 045120_1-045130_11. ISSN 1098-0121
|
PDF
- Author Version
391kB |
Official URL: http://prb.aps.org/abstract/PRB/v82/i4/e045120
Related URL: http://dx.doi.org/10.1103/PhysRevB.82.045120
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 [S. Mondal, D. Sen, K. Sengupta, and R. Shankar, Phys. Rev. Lett. 104, 046403 (2010)]. For NMN junctions, we show that for Dirac fermions with Fermi velocity vF, the transport can be controlled using the exchange field 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 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 V0, we find that beyond a critical J, the criteria of conductance maxima changes from X=eV0d/ћvF=nπ to X=(n+½)π for integer n. Finally, we compute the subgap tunneling conductance of a normal-metal-magnetic film-superconductor 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.
Item Type: | Article |
---|---|
Source: | Copyright of this article belongs to The American Physical Society. |
ID Code: | 45521 |
Deposited On: | 28 Jun 2011 05:48 |
Last Modified: | 18 May 2016 01:45 |
Repository Staff Only: item control page