A nanosheet transistor
Precise control of superconductivity by voltage application
Graduate School of Engineering / Faculty of Engineering
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.
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)
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.