Photoinduced two-step insulator-metal transition in Ti4O7 via ultrafast time-resolved optical reflectivity

We report on the systematic investigation of hot carrier dynamics in Ti4O7 by ultrafast time-resolved optical reflectivity. We find the transient indication for its two-step insulator-metal (I-M) transition, i.e., from the long-range ordered bipolaron low-temperature insulating phase to the disorder...

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Bibliographic Details
Published in:Applied physics express 2018-09, Vol.11 (9)
Main Authors: Nie, Xu-Chen, Song, Hai-Ying, Zhang, Xiu, Liu, Shi-Bing, Li, Fan, Yue, Lili, Meng, Jian-Qiao, Duan, Yu-Xia, Zhao, Lin, Liu, Hai-Yun
Format: Article
Language:English
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Summary:We report on the systematic investigation of hot carrier dynamics in Ti4O7 by ultrafast time-resolved optical reflectivity. We find the transient indication for its two-step insulator-metal (I-M) transition, i.e., from the long-range ordered bipolaron low-temperature insulating phase to the disordered bipolaron high-temperature insulating phase at Tc1 and to the free-carrier metallic phase at Tc2. Our results reveal that photoexcitation can effectively reduce both Tc1 and Tc2 by increasing the pump fluence, allowing the light-control of the I-M transition. We address a phase diagram that provides a framework for the photoinduced I-M transition and helps the potential use of Ti4O7 for photoelectric and thermoelectric devices.
ISSN:1882-0778
1882-0786
DOI:10.7567/APEX.11.095802