Josephson effect in graphene SNS junction with a single localized defect

Abstract

Imperfections change essentially the electronic transport properties of graphene. Motivated by a recent experiment reporting on the possible application of graphene as junctions, we study transport properties in graphene-based junctions with single localized defect. We solve the Dirac-Bogoliubovde-Gennes equation with a single localized defect superconductor-normal(graphene)-superconductor (SNS) junction. We consider the properties of tunneling conductance and Josephson current through an undoped strip of graphene with heavily doped s-wave superconducting electrodes in the limit l def ≪ L ≪ ξ. We find that spectrum of Andreev bound states are modified in the presence of single localized defect in the bulk and the minimum tunneling conductance remains the same. The Josephson junction exhibits sign oscillations.

Magnetoabsorption of elliptically polarized electromagnetic radiation by graphene: The relaxation-time approximation and Monte Carlo method

“…(8) is replaced by a sum according to the trape zoid method. Then, this integral sum, the change in the electron momentum, and the electron displace ment are calculated in each interval in the cycle until the following condition is satisfied (9) The time point t i at which condition (9) is satisfied for the first time, is considered as the collision time point. The value of t i is stored to determine the average time between collisions, which should be known to compare the results of numerical and analytical calcu lations.…”

“…Heightened interest in the study of the nonlinear electromagnetic (EM) response of graphene structures is associated with their applicability in optoelectronics [1][2][3][4][5][6][7][8][9][10][11][12]. The study of the effect of the magnetic field on kinetic properties of graphene provides information on the effective mass, concentration, mobility, and free path time of charge carriers [1,13,14].…”

Josephson Effect in Graphene-Based Junctions

“…In this paper we study the Josephson effect in graphene based junctions [7][8][9][10][11][12][13] where superconductivity in graphene is induced by the proximity effect from two different types of superconducting external sheets. The junction considered is described by the Dirac-Bogoliubov-de-Gennes equation with appropriate boundary conditions imposed on the normal metalsuperconductor (NS) interface.…”

Conductance enhancement due to atomic potential fluctuations in graphene

“…Among relativistic like phenomena observed in graphene so far, there are two new types of the integer quantum Hall effect and the presence of minimal metallic conductivity of about one conductivity quantum [2]. Transport properties of graphene are interesting because of their unique topological structure [3][4][5][6]. There have been some reports on experimental study of transport in graphene [7].…”