practice of students from arab republic of egypt 2009
DESCRIPTION
EFFECT OF DIFFUSION CURRENT (DC) ON CAPACTIVELY COUPLED JOSEPHSON JUNCTIONS (CCJJ) COMPARATIVE STUDY BETWEEN CCJJ AND CCJJ+DC. Practice of students from ARAB REPUBLIC OF EGYPT 2009. PROJECT. TITLE : Comparative Study between CCJJ and CCJJ+DC STUDENTS : Mostafa El Demery - PowerPoint PPT PresentationTRANSCRIPT
EFFECT OF DIFFUSION CURRENT (DC) ON CAPACTIVELY COUPLED JOSEPHSON JUNCTIONS (CCJJ)
COMPARATIVE STUDY BETWEEN CCJJ AND CCJJ+DCCOMPARATIVE STUDY BETWEEN CCJJ AND CCJJ+DC
Practice of students from ARAB REPUBLIC OF EGYPTARAB REPUBLIC OF EGYPT
20092009
PROJECT
• TITLE: Comparative Study between CCJJ and CCJJ+DCComparative Study between CCJJ and CCJJ+DC
• STUDENTS: Mostafa El DemeryMostafa El Demery
• SUPERVISOR: DRDR. Yuri ShukrinovYuri Shukrinov
• LAB: Bogoliubov Laboratory of Theoretical Physics Bogoliubov Laboratory of Theoretical Physics (BLTP)(BLTP)
LAYOUT• Some History
• Josephson Effect
• Josephson Junctions
• Capacitively Coupled Josephson Junctions
• Our Investigation
Some History• 1911: Onnes discovered SuperconductivitySuperconductivity.
• 1933: Meissner and Ochsenfeld discovered the perfect diamagnetismperfect diamagnetism.
• 1950: London, Ginsburg and Landau formulated a phenomenological theories of Superconductivityphenomenological theories of Superconductivity.
• 1957: Bardeen, Cooper and Schrieffer formulated a microscopic theories of Superconductivitymicroscopic theories of Superconductivity.
Some History
• 1962: Josephson effect Josephson effect and Josephson Josephson JunctionsJunctions.
• 1963: Anderson experimentally verified SupercurrentSupercurrent to be existed.
Josephson Effect• Novel phenomena should arise in a weak electrical
contact between two superconductors (Josephson Junction).
• Supercurrent component in the net current flowing through the junction is responsible for these phenomena.
• Supercurrent is a function not of the voltage V across the junction but of the phase-difference Josephson PhaseJosephson Phase.
Josephson Junction
Jose
phso
n Eff
ect
Josephson JunctionsTypes
TypesTypes• Tunnel Junctions (SIS Sandwich)1. Proposed in 1960 by Giaever.2. Superconductor (S)-insulator (I)-superconductor (S).3. Electrons have a small but nonvanishing probability
of penetrating from one electrode to the other one via quantum tunneling through the energy barrier by the insulator.
4. Electron penetration results in a nonvanishing normal conductance Gn when the electrodes are in
Normal State Superconducting State
S SI
Tunnel Junction
S S
N
Weak Link
Josephson JunctionsTypes (cont.)
TypesTypes• Weak Link (SNS Sandwich)
Capacitively Coupled Josephson Junctions
• System of superconducting layers with indices l and order parameter
and time-dependent phase
• Gauge invariant phase difference
Capacitively Coupled Josephson Junctions
• Generalized Josephson Relation GJR
• α is the coupling constant between junctions.
Comparative Study between CCJJ and CCJJ+DCComparative Study between CCJJ and CCJJ+DC
CCJJ• Total current flowing
through junctions is
CCJJ+DC• Total current flowing
through junctions is
System of dynamical equations for the phase difference
Comparative Study between CCJJ and CCJJ+DC (Cont.)Comparative Study between CCJJ and CCJJ+DC (Cont.)CCJJ
CCJJ+DC
With
out N
oise
P
erio
dic
BCs
W
ith N
oise
Comparative Study between CCJJ and CCJJ+DC (Cont.)Comparative Study between CCJJ and CCJJ+DC (Cont.)CCJJ
CCJJ+DC
With
out N
oise
Non
Per
iodi
c BC
s
W
ith N
oise
Comparative Study between CCJJ and CCJJ+DC (Cont.)Comparative Study between CCJJ and CCJJ+DC (Cont.)CCJJ
CCJJ+DC
Interjunction coupling between IJJInterjunction coupling between IJJCCJJ
Thank you for attention
Acknowledgement