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Cooper pair cotunneling in single charge transistors with dissipative electromagnetic environment
S V Lotkhov1, S A Bogoslovsky, A B Zorin
1Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany.
Physical Review Letters
|November 13, 2003
Summary
We studied superconducting single charge transistors and found Cooper pair cotunneling is suppressed by increasing resistance. Gate charge also modulates Josephson coupling and cotunneling currents.
Area of Science:
- Solid State Physics
- Quantum Computing
- Superconductivity
Background:
- Superconducting single charge transistors are key components in quantum circuits.
- Understanding charge transport mechanisms like Cooper pair cotunneling is crucial for device performance.
Purpose of the Study:
- To investigate the current-voltage characteristics of superconducting single charge transistors.
- To analyze the role of on-chip resistors and gate-induced charge on Cooper pair cotunneling.
- To determine the effect of resistance on cotunneling current suppression.
Main Methods:
- Fabrication and characterization of superconducting single charge transistors with integrated resistors.
- Measurement of current-voltage characteristics at varying gate charges and resistances.
- Theoretical analysis based on Cooper pair cotunneling models.
Main Results:
- Observed current-voltage characteristics explained by Cooper pair cotunneling.
- Demonstrated modulation of Josephson coupling strength and cotunneling current by gate charge.
- Found significant suppression of Cooper pair current at small voltages with increasing resistance (R).
Conclusions:
- Cooper pair cotunneling is a dominant transport mechanism in these devices.
- Gate-induced charge offers a method to tune transistor properties.
- Device resistance plays a critical role in suppressing cotunneling currents, impacting device performance.