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Main Authors: Watanabe, Hiroshi, Takeno, Yusuke, Negoro, Yusuke, Ikeda, Ryohei, Shibata, Yuria, Chen, Yitong, Nakamura, Takuto, Yamagami, Kohei, Hirata, Yasuyuki, Zhang, Yujun, Takahashi, Ryunosuke, Wadati, Hiroki, Tamasaku, Kenji, Imura, Keiichiro, Suzuki, Hiroyuki S., Sato, Noriaki K., Kimura, Shin-ichi
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2410.00674
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author Watanabe, Hiroshi
Takeno, Yusuke
Negoro, Yusuke
Ikeda, Ryohei
Shibata, Yuria
Chen, Yitong
Nakamura, Takuto
Yamagami, Kohei
Hirata, Yasuyuki
Zhang, Yujun
Takahashi, Ryunosuke
Wadati, Hiroki
Tamasaku, Kenji
Imura, Keiichiro
Suzuki, Hiroyuki S.
Sato, Noriaki K.
Kimura, Shin-ichi
author_facet Watanabe, Hiroshi
Takeno, Yusuke
Negoro, Yusuke
Ikeda, Ryohei
Shibata, Yuria
Chen, Yitong
Nakamura, Takuto
Yamagami, Kohei
Hirata, Yasuyuki
Zhang, Yujun
Takahashi, Ryunosuke
Wadati, Hiroki
Tamasaku, Kenji
Imura, Keiichiro
Suzuki, Hiroyuki S.
Sato, Noriaki K.
Kimura, Shin-ichi
contents To investigate the role of the excitons for the origin of the pressure-induced phase transition (BGT) from the black-colored insulator (BI) to the golden-yellow-colored metal (GM) of samarium monosulfide (SmS), optical reflectivity, Sm $3d$ X-ray absorption spectroscopy (XAS), and X-ray diffraction (XRD) with the creation of excitons by photoexcitation (PE) are reported. In the pump-probe reflectivity measurement, following a huge reflectivity change of about 22 %, three different relaxation times with a vibration component were observed. The fast component with the relaxation time ($τ$) of less than 1 ps is due to the excitation and relaxation of electrons into the conduction band, and the slowest one with $τ> {\rm several} 100$ ps originates from the appearance of the photo-induced (PI) state. The components with $τ\sim 10$ ps and vibration originate from the appearance of the PI state and the interference between the reflection lights at the sample surface and the boundary between the BI and PI states, suggesting that the electronic structure of the PI phase is different from that of the BI state. XAS spectra indicate that the Sm mean valence is shifted from the Sm$^{2+}$ dominant to the intermediate between Sm$^{2+}$ and Sm$^{3+}$ by PE but did not change to that of the GM phase across BGT, consistent with the reflectivity data. The XRD result after PE shows that the PI state has much less lattice contraction than the GM phase. These results suggest that the BGT cannot be achieved solely by creating excitons after PE but requires other effects, such as a lattice contraction.
format Preprint
id arxiv_https___arxiv_org_abs_2410_00674
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Photo-induced phase transition on black samarium monosulfide
Watanabe, Hiroshi
Takeno, Yusuke
Negoro, Yusuke
Ikeda, Ryohei
Shibata, Yuria
Chen, Yitong
Nakamura, Takuto
Yamagami, Kohei
Hirata, Yasuyuki
Zhang, Yujun
Takahashi, Ryunosuke
Wadati, Hiroki
Tamasaku, Kenji
Imura, Keiichiro
Suzuki, Hiroyuki S.
Sato, Noriaki K.
Kimura, Shin-ichi
Strongly Correlated Electrons
To investigate the role of the excitons for the origin of the pressure-induced phase transition (BGT) from the black-colored insulator (BI) to the golden-yellow-colored metal (GM) of samarium monosulfide (SmS), optical reflectivity, Sm $3d$ X-ray absorption spectroscopy (XAS), and X-ray diffraction (XRD) with the creation of excitons by photoexcitation (PE) are reported. In the pump-probe reflectivity measurement, following a huge reflectivity change of about 22 %, three different relaxation times with a vibration component were observed. The fast component with the relaxation time ($τ$) of less than 1 ps is due to the excitation and relaxation of electrons into the conduction band, and the slowest one with $τ> {\rm several} 100$ ps originates from the appearance of the photo-induced (PI) state. The components with $τ\sim 10$ ps and vibration originate from the appearance of the PI state and the interference between the reflection lights at the sample surface and the boundary between the BI and PI states, suggesting that the electronic structure of the PI phase is different from that of the BI state. XAS spectra indicate that the Sm mean valence is shifted from the Sm$^{2+}$ dominant to the intermediate between Sm$^{2+}$ and Sm$^{3+}$ by PE but did not change to that of the GM phase across BGT, consistent with the reflectivity data. The XRD result after PE shows that the PI state has much less lattice contraction than the GM phase. These results suggest that the BGT cannot be achieved solely by creating excitons after PE but requires other effects, such as a lattice contraction.
title Photo-induced phase transition on black samarium monosulfide
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2410.00674