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A nanosheet transistor Precise control of superconductivity by voltage application

February 28, 2013

Project Lecturer Jianting Ye and Professor Yoshihiro Iwasa’s research group at the University of Tokyo Graduate School of Engineering Quantum-Phase Electronics Center have produced a field-effect transistor of molybdenum disulfide, a material that is attracting researchers’ attention as a novel nanosheet material and alternative to graphene. The researchers demonstrated that this transistor showed excellent characteristics, and also demonstrated the controlled expression of superconductivity by the application of a voltage.

Device structure used in the present study
© Iwasa Laboratory

MoS2 nano-sheet showed superior transistor performance. A twin gate structure allowed fine tuning of superconductivity.

Materials research for low power consumption transistors has focused on oxides and organic materials, but single-atom-thick graphene nanosheets have also been considered a strong contender. However, graphene’s narrow band-gap and poor switching characteristics have prompted researchers to search for alternative materials with a wider band gap. The research group focused on molybdenum disulfide (MoS2), which has long been used as a mechanical lubricant, and prepared a transistor using a gate insulator and electrical double layer. The researchers confirmed that MoS2 becomes superconducting below 10K when a voltage is applied, and succeeded in continuously changing the transition temperature by varying the applied voltage.

The present study, in addition to providing a powerful means of controlling superconductivity, has shown that MoS2 and its class of similar materials are leading candidates for nanosheet materials to replace graphene.

Press release [pdf] (Japanese)

Paper

J. T. Ye, Y. J. Zhang, R. Akashi, M. S. Bahramy, R. Arita, and Y. Iwasa,
“Superconducting Dome in a Gate-Tuned Band Insulator”,
Science vol.338, 2012: 1193-1196, doi: 10.1126/science.1228006.
Article link

Links

Graduate School of Engineering

Quantum-Phase Electronics Center, Graduate School of Engineering

Iwasa Laboratory, Graduate School of Engineering

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