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arXiv · 0806.2642

Gate Tunable Dissipation and "Superconductor-Insulator" Transition in Carbon Nanotube Josephson Transistors

Gang Liu·Yong Zhang·Chun Ning Lau
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Abstract

Dissipation is ubiquitous in quantum systems, and its interplay with fluctuations is critical to maintaining quantum coherence. We experimentally investigate the dissipation dynamics in single-walled carbon nanotubes coupled to superconductors. The voltage-current characteristics display gate-tunable hysteresis, with sizes that perfectly correlate with the normal state resistance RN, indicating the junction undergoes a periodic modulation between underdamped and overdamped regimes. Surprisingly, when a device's Fermi-level is tuned through a local conductance minimum, we observe a gate-controlled transition from superconducting-like to insulating-like states, with a "critical" R_N value of about 8-20 kohm.

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Gang Liu, Yong Zhang, Chun Ning Lau. 2008-11-21. Gate Tunable Dissipation and "Superconductor-Insulator" Transition in Carbon Nanotube Josephson Transistors. https://doi.org/10.1103/physrevlett.102.016803

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