Molecular orbital formation and metastable short-range ordered structure in VO${}_2$

Abstract

The metal-insulator transition (MIT) in vanadium dioxide VO${}_2$ due to V-V dimerization has been extensively discussed for decades. While it is widely acknowledged that electron correlations, Peierls instabilities, and molecular orbital formations are crucial for understanding the MIT of VO${}_2$, the primary origin of the MIT remains controversial. In this study, we delve into the crystal structure and orbital state of VO${}_2$ through synchrotron x-ray diffraction experiments. The molecular orbital formation corresponding to the V-V dimerization is directly observed in the low-temperature insulating monoclinic phase, called the M1 phase, as indicated by the valence electron density distribution. Moreover, diffuse scattering observed in the high-temperature metal phase of rutile structure suggests the presence of short-range correlation of V displacements, which is not directly attributed to the structural fluctuation of the M1 phase. The short-range order in the rutile phase will be the key to understanding the MIT in this system.

arXiv comment6 pages, 4 figures, Supplemental Material

References in corpus (10)

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• Orbital-assisted metal-insulator transition in VO${}_2$
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• Uniting the order and disorder dynamics in photoexcited VO2
• Real-Space Observation of Ligand Hole State in Cubic Perovskite SrFeO${}_3$

Cited by in corpus (4)

• Reexamination of the charge-ordered dimer pattern in the spinel compound CuIr2S4 using single-crystal synchrotron x-ray diffraction
• Visualization of spin-orbit entangled 4f electrons in crystalline materials
• Linear tetramer formation in nonmagnetic pyrochlore niobate
• Current-induced successive structural phase transitions beyond thermal equilibrium in single-crystal VO2