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Related papers: Enhanced Andreev reflection in gapped graphene

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Spectra and spin structures of Andreev interface states and the Josephson current are investigated theoretically in junctions between clean superconductors (SC) with ordered interlayers. The Josephson current through the…

Superconductivity · Physics 2009-11-11 Yuri Barash , I. V. Bobkova , Brian M. Andersen , T. Kopp , P. J. Hirschfeld

A graphene superlattice is formed by a one-dimensional periodic potential and is characterized by the emergence of new Dirac points in the electronic structure. The group velocity of graphene's massless Dirac fermions at the new points is…

We report on a new type of Fano effect, named as Andreev-Fano effect, in a hybrid normal-metal / superconductor (N/S) interferometer embedded with a quantum dot. Compared with the conventional Fano effect, Andreev-Fano effect has some new…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Yu Zhu , Qing-feng Sun , Tsung-han Lin

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

We investigate the mesoscopic disorder induced rms conductance variance $\delta G$ in a few layer graphene nanoribbon (FGNR) contacted by two superconducting (S) Ti/Al contacts. By sweeping the back-gate voltage, we observe pronounced…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 J. Trbovic , N. Minder , F. Freitag , C. Schönenberger

In the "ballistic" regime, the transport across a normal metal (N)/superconductor (S) point-contact is dominated by a quantum process called Andreev reflection. Andreev reflection causes an enhancement of the conductance below the…

Superconductivity · Physics 2021-10-04 Ritesh Kumar , Goutam Sheet

We calculate the conductance of a junction between a disordered superconductor and a very strong half-metallic ferromagnet admitting electrons with only one spin projection. A usual mechanism of Andreev reflection is strongly suppressed in…

Superconductivity · Physics 2024-01-29 M. E. Ismagambetov , P. M. Ostrovsky , M. V. Feigel'man

We study the electron transport through a graphene nanoribbon-superconductor junction. Both zigzag and armchair edge graphene nanoribbons are considered, and the effects of the magnetic field and disorder on the transport property are…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 Qing-feng Sun , X. C. Xie

Andreev reflection at the interface between a half-metallic ferromagnet and a spin-singlet superconductor is possible only if it is accompanied by a spin flip. Here we calculate the Andreev reflection amplitudes for the case that the spin…

Mesoscale and Nanoscale Physics · Physics 2015-05-20 Joern N. Kupferschmidt , Piet W. Brouwer

We analyze the properties of flat-band superconductor junctions that behave differently from ordinary junctions containing only metals with Fermi surfaces. In particular, we show how in the tunneling limit the critical Josephson current…

Superconductivity · Physics 2025-09-08 P. Virtanen , R. P. S. Penttilä , P. Törmä , A. Díez-Carlón , D. K. Efetov , T. T. Heikkilä

Andreev reflection spectroscopy of ferromagnet/superconductor (FS) junctions is an important probe of spin polarization. We theoretically investigate spin-polarized transport in FS junctions in the presence of Rashba and Dresselhaus…

Superconductivity · Physics 2015-09-24 Petra Högl , Alex Matos-Abiague , Igor Žutić , Jaroslav Fabian

We investigate the crossed Andreev reflections between two graphene leads connected by a narrow superconductor. When the leads are respectively of the n-and p- type, we find that electron elastic cotunneling and local Andreev reflection are…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 J. Cayssol

The Josephson Effect and Superconducting Proximity Effect were observed in Superconductor -Graphene-Superconductor (SGS) Josephson junctions with coherence lengths comparable to the distance between the superconducting leads. By comparing…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Xu Du , Ivan Skachko , Eva Y. Andrei

The electron transport though ferromagnetic metal-superconducting hybrid devices is considered in the non-equilibrium Green's function formalism in the quasiclassical approximation. Attention if focused on the limit in which the exchange…

Superconductivity · Physics 2009-10-31 W. Belzig , Arne Brataas , Yu. V. Nazarov , Gerrit E. W. Bauer

Andreev reflection (AR) in ferromagnet/superconductor junctions is an indispensable spectroscopic tool for measuring spin polarization. We study theoretically how the presence of a thin semiconducting interface in such junctions, inducing…

Superconductivity · Physics 2019-09-11 Andreas Costa , Alex Matos-Abiague , Jaroslav Fabian

We study tunneling in ferromagnet/unconventional superconductor (F/S) junctions. We include the effects of spin polarization, interfacial resistance, and Fermi wavevector mismatch (FWM) between the F and S regions. Andreev reflection (AR)…

Superconductivity · Physics 2009-10-31 Igor Zutic , Oriol T. Valls

The Andreev reflection amplitude at a clean interface between a half-metallic ferromagnet (H) and a superconductor (S) for which the half metal's magnetization has a gradient perpendicular to the interface is proportional to the excitation…

Mesoscale and Nanoscale Physics · Physics 2015-06-04 Francis B. Wilken , Piet W. Brouwer

Monolayer graphene with an energy gap presents a pseudospin symmetry broken ferromagnet with a perpendicular pseudomagnetization whose direction is switched by altering the type of doping between n and p. We demonstrate an electrical…

Mesoscale and Nanoscale Physics · Physics 2015-05-30 Leyla Majidi , Malek Zareyan

We have studied the interplay of Andreev reflection and cyclotron motion of quasiparticles at a superconductor-normal-metal interface with a strong magnetic field applied parallel to the interface. Bound states are formed due to the…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 H. Hoppe , U. Zuelicke , Gerd Schoen

We study the interplay between proximity-induced superconductivity and ferromagnetism in graphene by self-consistently solving the Bogoliubov-de Gennes equations on the honeycomb lattice. We find that a strong triplet proximity effect is…

Superconductivity · Physics 2015-05-18 Jacob Linder , Annica M. Black-Schaffer , Asle Sudbø