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Unraveling metal-insulator transition mechanism of VO₂ triggered by tungsten doping.

ABSTRACT: Understanding the mechanism of W-doping induced reduction of critical temperature (T(C)) for VO(2) metal-insulator transition (MIT) is crucial for both fundamental study and technological application. Here, using synchrotron radiation X-ray absorption spectroscopy combined with first-principles calculations, we unveil the atomic structure evolutions of W dopant and its role in tailoring the T(C) of VO(2) MIT. We find that the local structure around W atom is intrinsically symmetric with a tetragonal-like structure, exhibiting a concentration-dependent evolution involving the initial distortion, further repulsion, and final stabilization due to the strong interaction between doped W atoms and VO(2) lattices across the MIT. These results directly give the experimental evidence that the symmetric W core drives the detwisting of the nearby asymmetric monoclinic VO(2) lattice to form rutile-like VO(2) nuclei, and the propagations of these W-encampassed nuclei through the matrix lower the thermal energy barrier for phase transition.

SUBMITTER: Tan X

PROVIDER: S-EPMC3381290 | biostudies-other | 2012

REPOSITORIES: biostudies-other

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