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Andreev reflection near the Dirac point at the graphene-NbSe2 junction

Sahu, Manas Ranjan and Raychaudhuri, Pratap and Das, Anindya (2016) Andreev reflection near the Dirac point at the graphene-NbSe2 junction. In: PHYSICAL REVIEW B, 94 (23).

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Official URL: http://dx.doi.org/10.1103/PhysRevB.94.235451

Abstract

Despite extensive search for about a decade, specular Andreev reflection (SAR) has only recently been realized in the bilayer graphene-superconductor interface. The experimental observation of retro to specular Andreev reflection is not only fundamentally important, but also has potential application in quantum computing, etc. Here we have carried out the transport measurements at the van der Waals interface of single-layer graphene and NbSe2 superconductor. We investigate the Andreev reflection near the Dirac point by measuring the differential conductance as a function of Fermi energy and bias energy. We find that the normalized conductance (G(T<Tc) /G(T>Tc)) becomes suppressed as we pass through the Dirac cone, which manifests the transition from retro to nonretro-type Andreev reflection. The suppression indicates the blockage of Andreev reflection beyond a critical angle (theta(c)) of the incident electron with respect to the normal between the single-layer graphene and the superconductor junction. However, the observation of SAR was restricted due to the finite Fermi-energy broadening. The results are compared with a theoretical model of the corresponding setup.

Item Type: Journal Article
Additional Information: Copy right for this article belongs to the AMER PHYSICAL SOC, ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Depositing User: Id for Latest eprints
Date Deposited: 31 Jan 2017 05:34
Last Modified: 31 Jan 2017 05:34
URI: http://eprints.iisc.ac.in/id/eprint/56177

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