Photo-induced semimetallic states realised in electron–hole coupled insulators

Kozo Okazaki, Yu Ogawa, Takeshi Suzuki, Takashi Yamamoto, Takashi Someya, Shoya Michimae, Mari Watanabe, Yangfan Lu, Minoru Nohara, Hidenori Takagi, Naoyuki Katayama, Hiroshi Sawa, Masami Fujisawa, Teruto Kanai, Nobuhisa Ishii, Jiro Itatani, Takashi Mizokawa, Shik Shin

    Research output: Contribution to journalArticle

    6 Citations (Scopus)

    Abstract

    Using light to manipulate materials into desired states is one of the goals in condensed matter physics, since light control can provide ultrafast and environmentally friendly photonics devices. However, it is generally difficult to realise a photo-induced phase which is not merely a higher entropy phase corresponding to a high-temperature phase at equilibrium. Here, we report realisation of photo-induced insulator-to-metal transitions in Ta2Ni(Se1−xSx)5 including the excitonic insulator phase using time- and angle-resolved photoemission spectroscopy. From the dynamic properties of the system, we determine that screening of excitonic correlations plays a key role in the timescale of the transition to the metallic phase, which supports the existence of an excitonic insulator phase at equilibrium. The non-equilibrium metallic state observed unexpectedly in the direct-gap excitonic insulator opens up a new avenue to optical band engineering in electron–hole coupled systems.

    Original languageEnglish
    Article number4322
    JournalNature Communications
    Volume9
    Issue number1
    DOIs
    Publication statusPublished - 2018 Dec 1

    Fingerprint

    Condensed matter physics
    insulators
    Optics and Photonics
    Light
    Photoelectron Spectroscopy
    Photonic devices
    Physics
    Entropy
    Photoelectron spectroscopy
    Transition metals
    Screening
    Metals
    Equipment and Supplies
    condensed matter physics
    Temperature
    dynamic characteristics
    photoelectric emission
    screening
    transition metals
    engineering

    ASJC Scopus subject areas

    • Chemistry(all)
    • Biochemistry, Genetics and Molecular Biology(all)
    • Physics and Astronomy(all)

    Cite this

    Okazaki, K., Ogawa, Y., Suzuki, T., Yamamoto, T., Someya, T., Michimae, S., ... Shin, S. (2018). Photo-induced semimetallic states realised in electron–hole coupled insulators. Nature Communications, 9(1), [4322]. https://doi.org/10.1038/s41467-018-06801-1

    Photo-induced semimetallic states realised in electron–hole coupled insulators. / Okazaki, Kozo; Ogawa, Yu; Suzuki, Takeshi; Yamamoto, Takashi; Someya, Takashi; Michimae, Shoya; Watanabe, Mari; Lu, Yangfan; Nohara, Minoru; Takagi, Hidenori; Katayama, Naoyuki; Sawa, Hiroshi; Fujisawa, Masami; Kanai, Teruto; Ishii, Nobuhisa; Itatani, Jiro; Mizokawa, Takashi; Shin, Shik.

    In: Nature Communications, Vol. 9, No. 1, 4322, 01.12.2018.

    Research output: Contribution to journalArticle

    Okazaki, K, Ogawa, Y, Suzuki, T, Yamamoto, T, Someya, T, Michimae, S, Watanabe, M, Lu, Y, Nohara, M, Takagi, H, Katayama, N, Sawa, H, Fujisawa, M, Kanai, T, Ishii, N, Itatani, J, Mizokawa, T & Shin, S 2018, 'Photo-induced semimetallic states realised in electron–hole coupled insulators', Nature Communications, vol. 9, no. 1, 4322. https://doi.org/10.1038/s41467-018-06801-1
    Okazaki K, Ogawa Y, Suzuki T, Yamamoto T, Someya T, Michimae S et al. Photo-induced semimetallic states realised in electron–hole coupled insulators. Nature Communications. 2018 Dec 1;9(1). 4322. https://doi.org/10.1038/s41467-018-06801-1
    Okazaki, Kozo ; Ogawa, Yu ; Suzuki, Takeshi ; Yamamoto, Takashi ; Someya, Takashi ; Michimae, Shoya ; Watanabe, Mari ; Lu, Yangfan ; Nohara, Minoru ; Takagi, Hidenori ; Katayama, Naoyuki ; Sawa, Hiroshi ; Fujisawa, Masami ; Kanai, Teruto ; Ishii, Nobuhisa ; Itatani, Jiro ; Mizokawa, Takashi ; Shin, Shik. / Photo-induced semimetallic states realised in electron–hole coupled insulators. In: Nature Communications. 2018 ; Vol. 9, No. 1.
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