Unraveling metal-insulator transition mechanism of VO₂ triggered by tungsten doping.
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.
Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei 230026, China.
Xiaogang
X
Tan
Tao
T
Yao
Ran
R
Long
Zhihu
Z
Sun
Yajuan
Y
Feng
Hao
H
Cheng
Xun
X
Yuan
Wenqing
W
Zhang
Qinghua
Q
Liu
Changzheng
C
Wu
Yi
Y
Xie
Shiqiang
S
Wei
D008670:Metals / Q000737:chemistry*; D008958:Models, Molecular; D044367:Phase Transition; D017356:Synchrotrons; D044366:Transition Temperature; D014414:Tungsten / Q000737:chemistry*; D017968:Vanadium Compounds / Q000737:chemistry*; D056928:X-Ray Absorption Spectroscopy; D014961:X-Ray Diffraction
D008670:Metals; D017968:Vanadium Compounds; D014414:Tungsten