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We study the effect of a structural nanoconstriction on the coherent transport properties of otherwise ideal zig-zag-edged infinitely long graphene ribbons. The electronic structure is calculated with the standard one-orbital tight-binding…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 F. Muñoz-Rojas , D. Jacob , J. Fernández-Rossier , J. J. Palacios

We demonstrate enhanced robustness of the supercurrent through graphene-based Josephson junctions in which strong spin-orbit interactions (SOIs) are induced. We compare the persistence of a supercurrent at high magnetic fields between…

Mesoscale and Nanoscale Physics · Physics 2021-01-06 T. Wakamura , N. J. Wu , A. D. Chepelianskii , S. Guéron , M. Och , M. Ferrier , T. Taniguchi , K. Watanabe , C. Mattevi , H. Bouchiat

I(V) characteristics and their first derivatives of ScS and ScN-type (S-superconductor, c-constriction, N-normal metal) point-contacts (PCs) based on Ba{1-x}NaxFe2As2 ($x$=0.25 and 0.35) were studied. ScS-type PCs with S=Nb,Ta and Pb show…

We solve the Dirac-Bogoliubov-De-Gennes equation in an impurity-free superconductor-normal-superconductor (SNS) junction, to determine the maximal supercurrent that can flow through an undoped strip of graphene with heavily doped…

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

We show how hydrogenation of graphene nanoribbons at small concentrations can open new venues towards carbon-based spintronics applications regardless of any especific edge termination or passivation of the nanoribbons. Density functional…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 D. Soriano , F. Muñoz-Rojas , J. Fernández-Rossier , J. J. Palacios

An intermittent Josephson effect in the form of voltage and temperature oscillations in the voltage - current curves near 2 K is observed in pellets consisting of superconducting TaC nanocapsules coated with graphite. This phenomenon is…

Superconductivity · Physics 2012-01-20 Dianyu Geng , Zhenhua Wang , Da Li , Zhidong Zhang , Xiaolin Wang

We study numerically the effects of edge and bulk disorder on the conductance of graphene nanoribbons. We compute the conductance suppression due to localization induced by edge scattering. We find that even for weak edge roughness,…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Eduardo R. Mucciolo , Antonio H. Castro Neto , Caio H. Lewenkopf

We investigate the combined influence of structural defects and uniaxial longitudinal strain on the electronic transport properties of armchair graphene nanoribbons using the numerical approach based on the semiempirical tight-binding…

Mesoscale and Nanoscale Physics · Physics 2013-09-30 Thomas Lehmann , Dmitry A. Ryndyk , Gianaurelio Cuniberti

We present a minimal but crucial microscopic theory for epitaxial graphene and graphene nanoribbons on the 4H-SiC(0001) surface -- protopypical materials to explore physical properties of graphene in large scale. Coarse-grained model…

Mesoscale and Nanoscale Physics · Physics 2009-12-08 Seungchul Kim , Jisoon Ihm , Hyoung Joon Choi , Young-Woo Son

We show that some of the Josephson couplings of junctions arranged to form an inhomogeneous network undergo a non-perturbative renormalization provided that the network's connectivity is pertinently chosen. As a result, the zero-voltage…

Superconductivity · Physics 2007-05-23 P. Sodano , A. Trombettoni , P. Silvestrini , R. Russo , B. Ruggiero

We have probed the superconducting proximity effect through long high-quality monocrystalline Ag nanowires, by realizing Josephson junctions of different lengths, with different superconducting materials. Thanks to the high number of…

Mesoscale and Nanoscale Physics · Physics 2021-01-04 A. Murani , S. Sengupta , A. Kasumov , R. Deblock , Caroline Celle , J-P. Simonato , H. Bouchiat , S. Guéron

The Josephson effect is a fundamental quantum phenomenon consisting in the appearance of a dissipationless supercurrent in a weak link between two superconducting (S) electrodes. While the mechanism leading to the Josephson effect is quite…

Mesoscale and Nanoscale Physics · Physics 2017-04-13 J. Paajaste , E. Strambini , M. Amado , S. Roddaro , P. San-Jose , R. Aguado , F. S. Bergeret , D. Ercolani , L. Sorba , F. Giazotto

We unveil the nature of the structural disorder in bottom-up zigzag graphene nanoribbons along with its effect on the magnetism and electronic transport on the basis of scanning probe microscopies and first-principles calculations. We find…

The stationary Josephson effect in a system of ballistic graphene is studied in the framework of quasiclassical Green's function theory. Reflecting the ultimate two-dimensionality of graphene, a Josephson junction involving a graphene sheet…

Mesoscale and Nanoscale Physics · Physics 2012-08-24 Yositake Takane , Ken-Ichiro Imura

We investigate the superconducting proximity effect through graphene in the long diffusive junction limit, at low and high magnetic field. The interface quality and sample phase coherence lead to a zero resistance state at low temperature,…

Mesoscale and Nanoscale Physics · Physics 2015-06-04 Katsuyoshi Komatsu , Chuan Li , S. Autier-Laurent , H. Bouchiat , S. Gueron

In this study, we examine multiple encapsulated graphene Josephson junctions to determine which mechanisms may be responsible for the supercurrent observed in the quantum Hall (QH) regime. Rectangular junctions with various widths and…

We investigate the critical current, $I_C$, of ballistic Josephson junctions made of encapsulated graphene/boron-nitride heterostructures. We observe a crossover from the short to the long junction regimes as the length of the device…

Mesoscale and Nanoscale Physics · Physics 2016-12-07 I. V. Borzenets , F. Amet , C. T. Ke , A. W. Draelos , M. T. Wei , A. Seredinski , K. Watanabe , T. Taniguchi , Y. Bomze , M. Yamamoto , S. Tarucha , G Finkelstein

We study the superconducting correlations induced in graphene when it is placed between two superconductors, focusing in particular on the supercurrents supported by the 2D system. For this purpose we make use of a formalism placing the…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 J. Gonzalez , E. Perfetto

The electronic and magnetic properties of zigzag graphene nanoribbons with asymmetric notches along their edges are investigated by first principle density functional theory calculations. It is found that the electronic and magnetic…

Mesoscale and Nanoscale Physics · Physics 2015-08-14 Guang-Yao Song , Qing-Hong Yuan , Wen-Xin Hu , De-Yan Sun

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