title: Decoupling the Lattice Distortion and Charge Doping Effects on the Phase Transition Behavior of VO2 by Titanium (Ti(4+)) Doping.
abstract: The mechanism for regulating the critical temperature (TC) of metal-insulator transition (MIT) in ions-doped VO2 systems is still a matter of debate, in particular, the unclear roles of lattice distortion and charge doping effects. To rule out the charge doping effect on the regulation of TC, we investigated Ti(4+)-doped VO2 (Ti(x)V(1-x)O2) system. It was observed that the TC of Ti(x)V(1-x)O2 samples first slightly decreased and then increased with increasing Ti concentration. X-ray absorption fine structure (XAFS) spectroscopy was used to explore the electronic states and local lattice structures around both Ti and V atoms in Ti(x)V(1-x)O2 samples. Our results revealed the local structure evolution from the initial anatase to the rutile-like structure around the Ti dopants. Furthermore, the host monoclinic VO2 lattice, specifically, the VO6 octahedra would be subtly distorted by Ti doping. The distortion of VO6 octahedra and the variation of TC showed almost the similar trend, confirming the direct effect of local structural perturbations on the phase transition behavior. By comparing other ion-doping systems, we point out that the charge doping is more effective than the lattice distortion in modulating the MIT behavior of VO2 materials.
authors.affiliation: State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University, Beijing. 100871, People's Republic of China.
authors.forename: Yanfei
authors.initials: Y
authors.lastname: Wu
authors.affiliation: National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei. 230029, People's Republic of China.
authors.forename: Lele
authors.initials: L
authors.lastname: Fan
authors.affiliation: National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei. 230029, People's Republic of China.
authors.forename: Qinghua
authors.initials: Q
authors.lastname: Liu
authors.affiliation: National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei. 230029, People's Republic of China.
authors.forename: Shi
authors.initials: S
authors.lastname: Chen
authors.affiliation: National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei. 230029, People's Republic of China.
authors.forename: Weifeng
authors.initials: W
authors.lastname: Huang
authors.affiliation: National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei. 230029, People's Republic of China.
authors.forename: Feihu
authors.initials: F
authors.lastname: Chen
authors.affiliation: National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei. 230029, People's Republic of China.
authors.forename: Guangming
authors.initials: G
authors.lastname: Liao
authors.affiliation: National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei. 230029, People's Republic of China.
authors.forename: Chongwen
authors.initials: C
authors.lastname: Zou
authors.affiliation: 1] National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei. 230029, People's Republic of China [2] Institute of High Energy Physics, Chinese Academy of Science, Beijing. 100049, People's Republic of China.
authors.forename: Ziyu
authors.initials: Z
authors.lastname: Wu