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“Gate-Controlled Suspended Titanium Nanobridge Supercurrent Transistor” published on ACS Nano

"Gate-Controlled Suspended Titanium Nanobridge Supercurrent Transistor" published on ACS Nano “Gate-Controlled Suspended Titanium Nanobridge Supercurrent Transistor” published on ACS Nano

Under standard conditions, the electrostatic field-effect is negligible in conventional metals and was expected to be completely ineffective also in superconducting metals. This common belief was recently put under question by a family of experiments that displayed full gate-voltage-induced suppression of critical current in superconducting all-metallic gated nanotransistors.

A new research carried out at the SQEL add an another piece to this intriguing puzzle showing the control of the supercurrent in fully suspended superconducting nanobridges.

The research, published on ACS Nano by M. Rocci and co-authors, allows to take a different perspective compared to previous studies and promise a better understanding of the field effect in superconducting metals, ruling out some of the hypothesis as possible mechanisms driving for the observed phenomenology.

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“Field-Effect Controllable Metallic Josephson Interferometer” published on Nano Letters

“Field-Effect Controllable Metallic Josephson Interferometer” published on Nano Letters “Field-Effect Controllable Metallic Josephson Interferometer” published on Nano Letters

A new research carried out at the SQEL report the realization of a titanium-based monolithic superconducting quantum interference device (SQUID) which can be tuned by applying a gate bias to its two Josephson junctions.

The research, published on Nano Letters by F. Paolucci and co-authors, points out the strong implications of the apparent coupling of a static electric field to the macroscopic phase of the superconducting condensate.

Beyond that, this class of quantum interferometers could represent a breakthrough for several applications such as digital electronics, quantum computing, sensitive magnetometry, and single-photon detection.

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SQEL students at NanoQI 2019

SQEL students at NanoQI'19 SQEL students at NanoQI’19

Advances in nanofabrication and the understanding and control of the quantum properties of matter are laying the groundwork for revolutionary new technologies and information processing capabilities. 

Four PhD students (L. Bours, A. Iorio, C. Puglia and F. Vischi) of the SQEL group were admitted to attend the 2019 Nanotechnology meets Quantum Information (NanoQI) summer school in Donostia-San Sebastián (Spain).  

Eight leading experts have been reviewed the experimental and theoretical state-of-the-art for some of the most promising implementations such as semiconductor quantum dots, superconducting circuits, topological insulators and much more.

During the school, our students showcased the research carried out at SQEL in three posters: “Field-effect metallic superconducting electronics” (by C. Puglia), “Field-effect controllable metallic Josephson interferometer” (by F. Vischi) and “Revealing the Spin-Orbit Interaction in InAs nanowires” (by A. Iorio).

  • Group picture at NanoQI’19
  • A. Iorio, F. Vischi and C. Puglia while presenting their posters at NanoQI’19
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Josephson Field-Effect Transistors Based on All-Metallic Al/Cu/Al Proximity Nanojunctions

"Josephson Field-Effect Transistors Based on All-Metallic Al/Cu/Al Proximity Nanojunctions" published on ACS Nano “Josephson Field-Effect Transistors Based on All-Metallic Al/Cu/Al Proximity Nanojunctions” published on ACS Nano

Researchers from SQEL have just realized field-effect controlled Josephson transistors based on proximity all-metallic mesoscopic superconductor-normal metal-superconductor junctions.

The research, published on ACS Nano by G. De Simoni and co-authors, suggests that the mechanism at the basis of the superconducting field-effect is quite general and does not rely on the existence of a true pairing potential, but rather the presence of superconducting correlations is enough for the effect to occur.

On the technological side, our findings widen the family of materials available for the implementation of all-metallic field-effect transistors to synthetic proximity-induced superconductors.