Femtosecond Charge Density Modulations in Photoexcited CuWO4
Uemura, Yohei; Ismail, Ahmed S.M.; Park, Sang Han; Kwon, Soonnam; Kim, Minseok; Niwa, Yasuhiro; Wadati, Hiroki; Elnaggar, Hebatalla; Frati, Federica; Haarman, Ties; Höppel, Niko; Huse, Nils; Hirata, Yasuyuki; Zhang, Yujun; Yamagami, Kohei; Yamamoto, Susumu; Matsuda, Iwao; Katayama, Tetsuo; Togashi, Tadashi; Owada, Shigeki; Yabashi, Makina; Halisdemir, Uufuk; Koster, Gertjan; Yokoyama, Toshihiko; Weckhuysen, Bert M.; De Groot, Frank M.F.
(2021) Journal of Physical Chemistry C, volume 125, issue 13, pp. 7329 - 7336
(Article)
Abstract
Copper tungstate (CuWO4) is an important semiconductor with a sophisticated and debatable electronic structure that has a direct impact on its chemistry. Using the PAL-XFEL source, we study the electronic dynamics of photoexcited CuWO4. The Cu L3 X-ray absorption spectrum shifts to lower energy upon photoexcitation, which implies that the
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photoexcitation process from the oxygen valence band to the tungsten conduction band effectively increases the charge density on the Cu atoms. The decay time of this spectral change is 400 fs indicating that the increased charge density exists only for a very short time and relaxes electronically. The initial increased charge density gives rise to a structural change on a time scale longer than 200 ps.
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Keywords: Electronic, Optical and Magnetic Materials, General Energy, Physical and Theoretical Chemistry, Surfaces, Coatings and Films
ISSN: 1932-7447
Publisher: American Chemical Society
Note: Funding Information: This work was financially supported by the European Research Council (ERC) under the European Union’s Horizon 2020 Research and Innovation Programme (Grant Agreement 340279), The Netherlands Center for Multiscale Catalytic Energy Conversion (MCEC), a Gravitation Program from The Netherlands Organisation for Scientific Research (NWO), a grant for collaborative research in the Institute for Catalysis, Hokkaido University (Grant 18A1005), a Grant-in-Aid for Scientific Research (A) (Grant 15H02173, JSPS), and a basic science research program funded by the Ministry of Education of Korea (Grants NRF-2020R1A2C1007416 and 2018R1D1A1B07046676). N. Huse and N. Höppel acknowledge funding by the collaborative research center SFB 925 of the German Science Foundation (DFG), project 170620586. The experiment at SACLA was performed with an approval of Japan Synchrotron Radiation Research Institute (JASRI; Proposal 2018A8049). We thank Prof. Thomas Elsasser (Max-Born Institute/Humboldt Universität zu Berlin) and Prof. Kiyotaka Asakura (Hokkaido University) for useful comments and suggestions. Funding Information: This work was financially supported by the European Research Council (ERC) under the European Union's Horizon 2020 Research and Innovation Programme (Grant Agreement 340279), The Netherlands Center for Multiscale Catalytic Energy Conversion (MCEC), a Gravitation Program from The Netherlands Organisation for Scientific Research (NWO), a grant for collaborative research in the Institute for Catalysis Hokkaido University (Grant 18A1005), a Grant-in-Aid for Scientific Research (A) (Grant 15H02173, JSPS), and a basic science research program funded by the Ministry of Education of Korea (Grants NRF-2020R1A2C1007416 and 2018R1D1A1B07046676). N. Huse and N. Hoppel acknowledge funding by the collaborative research center SFB 925 of the German Science Foundation (DFG), project 170620586. The experiment at SACLA was performed with an approval of Japan Synchrotron Radiation Research Institute (JASRI; Proposal 2018A8049). We thank Prof. Thomas Elsasser (Max-Born Institute/Humboldt Universitat zu Berlin) and Prof. Kiyotaka Asakura (Hokkaido University) for useful comments and suggestions. Publisher Copyright: © 2021 The Authors. Published by American Chemical Society.
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