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


研究成果: Article査読

62 被引用数 (Scopus)


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.

ジャーナルNature communications
出版ステータスPublished - 2018 12月 1

ASJC Scopus subject areas

  • 化学一般
  • 生化学、遺伝学、分子生物学一般
  • 物理学および天文学一般


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