Download Slide 1

Simulating current voltage
characteristics in Intrinsic
Josephson junctions
M. Hromnik
Yu. M. Shukrinov
M Gaafar
BLTP, JINR, Dubna , Russia
Layered Bi2Sr2CaCu2Oy(Bi2212) single
crystals represent natural stacks of atomic
scale intrinsic Josephson junctions.
I
S （３Å）
I （１２Å）
Ca
Cu
S
Sr
O
I
Bi
I-V characteristics
X:50mV/div
Y:100mA/div
– Multi-branch structure
– large hysteresis
– Roughly equal spacing
Applications of Josephson
Junctions
• Defines a Voltage standard - metrology
• Quantum computing – single electron transistors
• SQUIDS – superconducting quantum interface devices
•
able to measure magnetic fields down to 10^-18 T
STJs – Superconducting tunnel junction detectors which
make use of quantum electron tunneling through the JJ –
high speed electrical circuits
Numerical Procedure
4th order Runge Kutta method
• Heavy duty computation – O(10^9) time steps
• Intelligent data logging – on the fly averaging ensures a
•
•
•
manageable and meaningful output
Intelligent disk IO – buffering (significant effect of
performance)
Looping technique to match experimental method
Parallel computing options limited
Time dependence

div (0 E) = Q
Ql=Q0  (Vl+1-Vl)
Q0 =   0 V0/rD2
Current Voltage characteristics
Longitudinal Plasma Wave
Results from CJJ+DC model
Thank you!