“School of Nano-Sciences”
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| Paper IPM / Nano-Sciences / 18252 |
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| Abstract: | |||||
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We theoretically reveal the possibility of a specular Andreev reflection in a thin film topological insulator normal-superconductor (N/S) junction. We demonstrate that the gate-induced potential difference between the top and bottom surfaces of the thin film, denoted as U, and the coupling parameter between the two surfaces, denoted as ω, play critical roles in determining the probability of electron-hole conversion in specular Andreev reflection. The probability of specular Andreev reflection increases with U, and perfect electron-hole conversion with unit efficiency is achieved over a wide experimental range of the potential difference U. This perfect Andreev reflection exhibits strong robustness with respect to increasing the coupling parameter ω for normally incident electrons at the N/S interface when the excitation energy ε = ΔS (where ΔS is the superconducting gap). In contrast, the probability decreases with increasing ω for the condition ε < ΔS. Furthermore, we demonstrate that this perfect specular Andreev reflection can occur for all angles of incidence to the proposed N/S interface when the excitation energy satisfies ε = ΔS. These results indicate that the proposed topological insulator thin film-based N/S structure offers strong potential for realizing intra-band specular Andreev reflection.
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