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Paper   IPM / P / 14090
School of Physics
  Title:   Specular Andreev reflection in thin films of topological insulators
1.  L. Majidi
2.  R. Asgari
  Status:   Published
  Journal: Phys. Rev. B
  Vol.:  93
  Year:  2016
  Pages:   195404
  Supported by:  IPM
We theoretically reveal the possibility of a specular Andreev reflection in a thin film topological insulator normal-superconductor (N/S) junction. We demonstrate the determining effects of the gate-induced potential difference of the up and down surfaces of the thin film (U), and the coupling parameter of the two surfaces (ω) on the probability of the electron-hole conversion in a specular Andreev reflection. The probability of the specular Andreev reflection increases with U and the electron-hole conversion with unit efficiency happens in a wide experimental range of the potential difference U. This perfect Andreev reflection is found to show strong robustness with respect to increasing the coupling parameter ω for normally incident electrons to the N/S interface with the excitation energy ε = ∆S (∆S is the superconducting gap), while it decreases with ω for ε < ∆S. We further demonstrate that this perfect specular Andreev reflection can be occurred for all angles of incidence to the proposed N/S interface with ε = ∆S. Our results reveal the potential of the proposed topological insulator thin film-based N/S structure for the realization of the intra-band specular Andreev reflection.

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