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Research Center of Integrative Molecular Systems Yamamoto Group

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Location: Myoudaiji, South Laboratory Bldg. Room304
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Molecular Conductors, Organic Superconducting Transistors, Supramolecular Nanowires

Open up Future Electronics by Organic Molecules

Organic molecules are attracting recent attention as new ingredients of electronic circuits. Their functionalities have been developed considerably, but are still to be explored and advanced. Our group focuses on a development of organic electronics in the next era by providing new mechanism and concepts of the device operation and fabrication. For example, an electronic phase transition is utilized for the ON/OFF switching of our field-effect-transistor (FET). This special FET is called an organic Mott-FET, where the conduction electrons in the organic semiconductor are solidified at the OFF state because of Coulomb repulsion among carriers. However, these solidified electrons can be melted by applying a gate voltage, and show an insulator-to-metal transition so-called Mott-transition to be switched to the ON state. Because of this phase transition, a large response of the device can be achieved, resulting in the highest device mobility ever observed for organic FETs. At the same time, Mott-transition is known for its relevance to superconductivity. Not only in organic materials but also in inorganic materials such as cuprates, Mott-transition is frequently associated with superconducting phase at low temperature. Indeed, our organic FET shows an electric-field-induced superconducting transition at low temperature.

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Light-induced superconductivity at an organic interface. Self-assembled monolayer (SAM) of photochromic molecule can react with UV light to form electric field across the interface. This electric field invites excess carriers that induces superconductivity from Mott-insulating state.

Selected Publications

  1. H. M. Yamamoto, M. Suda, and Y. Kawasugi “Organic phase-transition transistor with strongly correlated electrons” Jpn. J. Appl. Phys., 57, 03EA02 (2018).
  2. M. Suda, R. Kato, and H. M. Yamamoto "Light-induced superconductivity using a photo-active electric double layer" Science,347, 743-746 (2015).
  3. H. M. Yamamoto, M. Nakano, M. Suda, Y. Iwasa, M. Kawasaki and R. Kato
    "A strained organic field-effect transistor with a gate-tunable superconducting channel" Nature Commun. 4, 2379/1–2379/7 (2013)