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Decoupling the metal insulator transition and crystal field effects of VO2
- Source :
- Scientific Reports, Vol 11, Iss 1, Pp 1-13 (2021), Scientific Reports
- Publication Year :
- 2021
- Publisher :
- Nature Portfolio, 2021.
-
Abstract
- VO2 is a highly correlated electron system which has a metal-to-insulator transition (MIT) with a dramatic change of conductivity accompanied by a first-order structural phase transition (SPT) near room temperature. The origin of the MIT is still controversial and there is ongoing debate over whether an SPT induces the MIT and whether the Tc can be engineered using artificial parameters. We examined the electrical and local structural properties of Cr- and Co-ion implanted VO2 (Cr-VO2 and Co-VO2) films using temperature-dependent resistance and X-ray absorption fine structure (XAFS) measurements at the V K edge. The temperature-dependent electrical resistance measurements of both Cr-VO2 and Co-VO2 films showed sharp MIT features. The Tc values of the Cr-VO2 and Co-VO2 films first decreased and then increased relative to that of pristine VO2 as the ion flux was increased. The pre-edge peak of the V K edge from the Cr-VO2 films with a Cr ion flux ≥ 1013 ions/cm2 showed no temperature-dependent behavior, implying no changes in the local density of states of V 3d t2g and eg orbitals during MIT. Extended XAFS (EXAFS) revealed that implanted Cr and Co ions and their tracks caused a substantial amount of structural disorder and distortion at both vanadium and oxygen sites. The resistance and XAFS measurements revealed that VO2 experiences a sharp MIT when the distance of V–V pairs undergoes an SPT without any transitions in either the VO6 octahedrons or the V 3d t2g and eg states. This indicates that the MIT of VO2 occurs with no changes of the crystal fields.
- Subjects :
- Materials science
Science
Analytical chemistry
02 engineering and technology
01 natural sciences
Article
Ion
Crystal
Electrical resistance and conductance
0103 physical sciences
Metal–insulator transition
010306 general physics
Multidisciplinary
Local density of states
Extended X-ray absorption fine structure
Physics
021001 nanoscience & nanotechnology
X-ray absorption fine structure
K-edge
Medicine
0210 nano-technology
human activities
circulatory and respiratory physiology
Subjects
Details
- Language :
- English
- ISSN :
- 20452322
- Volume :
- 11
- Issue :
- 1
- Database :
- OpenAIRE
- Journal :
- Scientific Reports
- Accession number :
- edsair.doi.dedup.....27129b0bdfb9c001ee90d55c23964f5d