TY - JOUR
T1 - Emergence of metallic monoclinic states of VO2 films induced by K deposition
AU - Shiga, D.
AU - Minohara, M.
AU - Kitamura, M.
AU - Yukawa, R.
AU - Horiba, K.
AU - Kumigashira, H.
N1 - Funding Information:
The authors are very grateful to A. F. Santander-Syro, M. Lippmaa, and M. J. Rozenberg for the useful discussions. This work was financially supported by Grants-in-Aid for Scientific Research (No. 16H02115, No. 16KK0107, No. 17K14325, and No. 16K05033) from the Japan Society for the Promotion of Science (JSPS), CREST (JPMJCR18T1) from the Japan Science and Technology Agency (JST), and the MEXT Elements Strategy Initiative to Form Core Research Center. The work at KEK-PF was performed with the approval of the Program Advisory Committee (Proposals 2015S2-005, 2016G164, and 2018S2-004) at the Institute of Materials Structure Science at KEK.
Publisher Copyright:
© 2019 American Physical Society.
PY - 2019/3/14
Y1 - 2019/3/14
N2 - In order to study the origin of metallization of VO2 induced by electron injection, we deposit K atoms onto the surface of VO2 films grown on TiO2 (001) substrates, and we investigate the change in the electronic and crystal structures using in situ photoemission spectroscopy and x-ray absorption spectroscopy (XAS). The deposition of K atoms onto a surface of insulating monoclinic VO2 leads to a phase transition from insulator to metal. In this metallization state, the V-V dimerization characteristic to the monoclinic phase of VO2 still exists, as revealed by the polarization dependence of the XAS spectra. Furthermore, the monoclinic metal undergoes a transition to a monoclinic insulator with decrease in temperature, and to a rutile metal with increase in temperature. These results indicate the existence of a metallic monoclinic phase around the boundary between the insulating monoclinic and metallic rutile phases in the case of electron-doped VO2.
AB - In order to study the origin of metallization of VO2 induced by electron injection, we deposit K atoms onto the surface of VO2 films grown on TiO2 (001) substrates, and we investigate the change in the electronic and crystal structures using in situ photoemission spectroscopy and x-ray absorption spectroscopy (XAS). The deposition of K atoms onto a surface of insulating monoclinic VO2 leads to a phase transition from insulator to metal. In this metallization state, the V-V dimerization characteristic to the monoclinic phase of VO2 still exists, as revealed by the polarization dependence of the XAS spectra. Furthermore, the monoclinic metal undergoes a transition to a monoclinic insulator with decrease in temperature, and to a rutile metal with increase in temperature. These results indicate the existence of a metallic monoclinic phase around the boundary between the insulating monoclinic and metallic rutile phases in the case of electron-doped VO2.
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U2 - 10.1103/PhysRevB.99.125120
DO - 10.1103/PhysRevB.99.125120
M3 - Article
AN - SCOPUS:85063257976
VL - 99
JO - Physical Review B
JF - Physical Review B
SN - 2469-9950
IS - 12
M1 - 125120
ER -