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

doi:10.1038/s41467-018-06801-1

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

^*この研究の対応する著者

先進理工学部

研究成果: Article › 査読

59 被引用数 (Scopus)

抄録

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(Se_1−xS_x)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.

本文言語	English
論文番号	4322
ジャーナル	Nature communications
巻	9
号	1
DOI	https://doi.org/10.1038/s41467-018-06801-1
出版ステータス	Published - 2018 12月 1

ASJC Scopus subject areas

化学 (全般)
生化学、遺伝学、分子生物学（全般）
物理学および天文学（全般）

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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, 9(1), 記事 4322. https://doi.org/10.1038/s41467-018-06801-1

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

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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.",

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

note = "Funding Information: We would like to thank H. Fukuyama and Y. Ohta for valuable discussions and comments. This work was supported by JSPS KAKENHI (Grant nos. JP25220707 and JP26610095) and the Photon and Quantum Basic Research Coordinated Development Programme from the Ministry of Education, Culture, Sports, Science and Technology, Japan. T. Someya acknowledges the JSPS Research Fellowship for Young Scientists. Publisher Copyright: {\textcopyright} 2018, The Author(s).",

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AU - Michimae, Shoya

AU - Watanabe, Mari

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AU - Nohara, Minoru

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AU - Itatani, Jiro

AU - Mizokawa, Takashi

AU - Shin, Shik

N1 - Funding Information: We would like to thank H. Fukuyama and Y. Ohta for valuable discussions and comments. This work was supported by JSPS KAKENHI (Grant nos. JP25220707 and JP26610095) and the Photon and Quantum Basic Research Coordinated Development Programme from the Ministry of Education, Culture, Sports, Science and Technology, Japan. T. Someya acknowledges the JSPS Research Fellowship for Young Scientists. Publisher Copyright: © 2018, The Author(s).

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N2 - 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.

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

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