Publication: Magnetic gap effect on the tunneling conductance in a topological insulator ferromagnet/superconductor junction
Issued Date
2010-07-26
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ISSN
03759601
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2-s2.0-77955584363
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Mahidol University
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SCOPUS
Bibliographic Citation
Physics Letters, Section A: General, Atomic and Solid State Physics. Vol.374, No.34 (2010), 3561-3566
Suggested Citation
Bumned Soodchomshom Magnetic gap effect on the tunneling conductance in a topological insulator ferromagnet/superconductor junction. Physics Letters, Section A: General, Atomic and Solid State Physics. Vol.374, No.34 (2010), 3561-3566. doi:10.1016/j.physleta.2010.06.055 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/29948
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Title
Magnetic gap effect on the tunneling conductance in a topological insulator ferromagnet/superconductor junction
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Abstract
The tunneling conductance on the surface of a topological-insulator-based ferromagnet/superconductor (F/S) structure is studied where S is an s-wave superconductor with superconducting order parameter ∼Δ. The conductance is calculated based on the BTK formalism. The magnetization in F is applied along the z-direction (m→= 〈0, 0, M〉) in order to induce the energy-mass gaps (m) for the Dirac electrons in the F-region. In this work, the influence of energy gap due to the magnetic field in the F-region on the conductance is emphasized. The Fermi energy mismatch between F (EFF=EF) and S (EFS=EF+U), where the gate potential U is applied to the electrode on top of S, is also considered. As a result, a biased voltage V can cause the conductance switch at eV=Δ, depending on the value of the magnetic field. The conductance is found to be linearly dependent on either m or U. The slope of the curve can also be adjusted. This linear behavior in a topological-insulator- based F/S structure may be valuable for electronic applications of the linear-control-current devices. The tunneling conductances of the quasi-Dirac-particle in a topological-insulator-based F/S junction are quite different from those of a graphene-based F/S junction. © 2010 Elsevier B.V.