Pressure-induced phase transitions and insulator-metal transitions in VO2 nanoparticles

JOURNAL OF ALLOYS AND COMPOUNDS

卷:709

Article

Li, Quanjun^1,2  Zhang, Huafang¹  Lin, Chuanlong²  Tian, Fubo¹  Smith, Jesse S.^1,2  Park, Changyong²  Liu, Bingbing¹  Shen, Guoyin² 

[1] Jilin Univ, State Key Lab Superhard Mat, Changchun 130012, Peoples R China

[2] Carnegie Inst Sci, High Pressure Collaborat Access Team, Geophys Lab, Argonne, IL 60439 USA

关键词: VO2 High pressure;    Phase transition;    Metallization;    Strongly correlated materials;    Nanoparticles;   

DOI  :  10.1016/j.jallcom.2017.03.164

来源: Elsevier

【 摘 要 】

We present pressure-induced phase transitions and metallization in VO2 nanoparticles characterized by synchrotron x-ray diffraction, Raman spectroscopy, and infrared reflectivity measurements. The M1-M1'-Mx phase transitions were found in VO2 nanoparticles upon compression. The results of IR reflectivity shown that pressure-induced metallization occurs in the M1' phase with increasing pressure and the sample becomes fully metallic at the transition of MV to Mx. The metallic Mx phase transforms to metastable mixed phases displaying insulating properties upon decompression. We attribute the pressure-induced metallization of the M1' phase to the strong electron correlations, while the metal insulator transition (MIT) from the Mx to the mixed phases is found to be associated with the structural phase transitions. Both the electron-correlation-driven Mott transition and the structure-driven MIT can be achieved in VO2 by applying pressure. Compared with bulk samples, the VO2 nanoparticles exhibit larger bulk moduli and increased transition pressure due to their nanosize effects. High pressure provides an effective method to study the MIT in strongly correlated materials and paves the way for modifying electronic properties of VO2. (C) 2017 Elsevier B.V. All rights reserved.

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