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Related papers: Andreev reflection in bilayer graphene

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We study the Andreev and normal reflection processes -- retro as well as specular -- in a bilayer graphene-superconductor junction where equal and opposite displacement fields are applied for the top and bottom layers to induce a band gap.…

Superconductivity · Physics 2023-11-17 Panch Ram , Detlef Beckmann , Romain Danneau , Wolfgang Belzig

By combining the Dirac equation of relativistic quantum mechanics with the Bogoliubov-De Gennes equation of superconductivity we investigate the electron-hole conversion at a normal-metal--superconductor interface in graphene. We find that…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 C. W. J. Beenakker

Despite extensive search for about a decade, specular Andreev reflection is only recently realized in bilayer graphene-superconductor interface. However, the evolution from the typical retro type Andreev reflection to the unique specular…

Mesoscale and Nanoscale Physics · Physics 2017-01-04 Manas Ranjan Sahu , Pratap Raychaudhuri , Anindya Das

We numerically investigate Andreev reflection in a graphene ring with one normal conducting and one superconducting lead by solving the Bogoliubov--de Gennes equation within the Landauer-B\"uttiker formalism. By tuning chemical potential…

Mesoscale and Nanoscale Physics · Physics 2012-03-19 Jörg Schelter , Björn Trauzettel , Patrik Recher

Electrons incident from a normal metal onto a superconductor are reflected back as holes - a process called Andreev reflection. In a normal metal where the Fermi energy is much larger than a typical superconducting gap, the reflected hole…

Mesoscale and Nanoscale Physics · Physics 2016-08-04 D. K. Efetov , L. Wang , C. Handschin , K. B. Efetov , J. Shuang , R. Cava , T. Taniguchi , K. Watanabe , J. Hone , C. R. Dean , P. Kim

We report on Andreev reflections at clean NbSe2-bilayer graphene junctions. The high transparency of the junction, which manifests as a large conductance enhancement of up to 1.8, enables us to see clear evidence of a proximity-induced…

Mesoscale and Nanoscale Physics · Physics 2020-05-06 Jing Li , Han-Bing Leng , Hailong Fu , Kenji Watanabe , Takashi Taniguchi , Xin Liu , Chao-Xing Liu , Jun Zhu

We study Andreev reflection in normal metal-superconductor junctions by using an extended Blonder-Tinkham-Klapwijk model combined with transport calculations based on density functional theory. Starting from a parameter-free description of…

Mesoscale and Nanoscale Physics · Physics 2014-10-28 Awadhesh Narayan , Ivan Rungger , Stefano Sanvito

The Andreev reflection of the normal state-superconductor junction both in monolayer and bilayer graphene with a single magnetic barrier is investigated by means of the Green's function formalism. Within the tight-binding model, we study…

Mesoscale and Nanoscale Physics · Physics 2013-05-07 Hengyi Xu , T. Henizel

We report the study of ballistic transport in normal metal/graphene/superconductor junctions in edge-contact geometry. While in the normal state, we have observed Fabry-P\'{e}rot resonances suggesting that charge carriers travel…

Mesoscale and Nanoscale Physics · Physics 2019-10-30 P. Pandey , R. Kraft , R. Krupke , D. Beckmann , R. Danneau

A graphene sheet partially covered with a bulk superconductor serves as a normal conductor--superconductor (NS) junction, in which electron transport is mainly governed by Andreev reflection (AR). As excess carriers induced over the covered…

Mesoscale and Nanoscale Physics · Physics 2017-06-28 Yositake Takane , Katsuhide Yarimizu , Akinobu Kanda

We evaluate the differential conductance measured in a scanning tunneling microscopy (STM) setting at arbitrary electron transmission between an STM tip and a two-dimensional (2D) superconductor with arbitrary gap structure. Our analytical…

Superconductivity · Physics 2023-05-30 P. O. Sukhachov , Felix von Oppen , L. I. Glazman

A ballistic strip of graphene (width W>> length L) connecting two normal metal contacts is known to have a minimum conductivity of 4e^{2}/pi h at the Dirac point of charge neutrality. We calculate what happens if one of the two contacts…

Mesoscale and Nanoscale Physics · Physics 2013-07-09 A. R. Akhmerov , C. W. J. Beenakker

Ongoing experimental progress in the preparation of ultra-clean graphene/superconductor (SC) interfaces enabled the recent observation of specular interband Andreev reflections (AR) at bilayer graphene (BLG)/NbSe$_{2}$ van der Waals…

Mesoscale and Nanoscale Physics · Physics 2016-08-10 Dmitri K. Efetov , Konstantin B. Efetov

We theoretically demonstrate unusual features of superconducting proximity effect in gapped graphene which presents a pseudospin symmetry-broken ferromagnet with a net pseudomagnetization. We find that the presence of a band gap makes the…

Mesoscale and Nanoscale Physics · Physics 2015-06-11 Leyla Majidi , Malek Zareyan

We investigate the Andreev reflection in a normal metal/charge-4e superconductor junction.Compare with the electron-hole conversion in normal charge-2e superconductors, here four electrons participate simultaneously, enriching the…

Superconductivity · Physics 2024-10-30 Yi-Xin Dai , Qing-Feng Sun

Andreev reflection in graphene is special since it can be of two types- retro or specular. Specular Andreev reflection (SAR) dominates when the position of the Fermi energy in graphene is comparable to or smaller than the superconducting…

Mesoscale and Nanoscale Physics · Physics 2018-08-07 Abhiram Soori , Manas Ranjan Sahu , Anindya Das , Subroto Mukerjee

We show that Andreev reflection in a junction between ferromagnetic (F) and superconducting (S) graphene regions is fundamentally different from the common FS junctions. For a weakly doped F graphene with an exchange field $h$ larger than…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Malek Zareyan , Hakimeh Mohammadpour , Ali G. Moghaddam

Coherent charge transport along ballistic paths can be introduced into graphene by Andreev reflection, for which an electron reflects from a superconducting contact as a hole, while a Cooper pair is transmitted. We use a liquid-helium…

Mesoscale and Nanoscale Physics · Physics 2020-08-26 S. Bhandari , G. -H. Lee , K. Watanabe , T. Taniguchi , P. Kim , R. M. Westervelt

The accurate and proper form of electron-hole excitations and corresponding Dirac-like spinors of monolayer molybdenum disulfide superconductor are exactly obtained. Andreev reflection and resulting subgap conductance in a $MoS_2$-based…

Mesoscale and Nanoscale Physics · Physics 2017-02-01 H. Goudarzi , M. Khezerlou , S. F. Ebadzadeh

We study Andreev reflection in graphene nanoribbon/superconductor hybrid junctions. By using a tight-binding approach and the scattering formalism we show that finite-size effects lead to notable differences with respect to the bulk…

Mesoscale and Nanoscale Physics · Physics 2009-03-28 Diego Rainis , Fabio Taddei , Fabrizio Dolcini , Marco Polini , Rosario Fazio
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