A Refinement of the Structure of VO2.

Longo, J.M.; Kierkegaard, Peder; Ballhausen, C. J.; Ragnarsson, Ulf; Rasmussen, Svend Erik; Sunde, Erling; Sørensen, Nils Andreas

doi:10.3891/acta.chem.scand.24-0420

Cited by 215 publications

(97 citation statements)

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“…From the literature, the 011 plane spacing ranges from 3.1978 Å and 3.2067 Å for bulk VO 2 . 30,31 Averaging the literature values implies a tensile strain in the out of plane direction of 0.89%. This type of tensile strain would result from compressive strains in the plane of the substrate.…”

Section: A Sample Strainmentioning

confidence: 73%

Modification of electronic structure in compressively strained vanadium dioxide films

Huffman

Hollingshad

et al. 2015

Phys. Rev. B

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Vanadium dioxide (VO 2 ) undergoes a phase transition between an insulating monoclinic (M 1 ) phase and a conducting rutile phase. Like other correlated electron systems, the properties of VO 2 can be extremely sensitive to small changes in external parameters such as strain. In this work, we investigate a compressively strained VO 2 film grown on [001] quartz substrate in which the phase transition temperature (T c ) has been depressed to 325K from the bulk value of 340K. Infrared and optical spectroscopy reveals that the lattice dynamics of this strained film are very similar to unstrained VO 2 . However, some of the electronic inter-band transitions of the strained VO 2 film are significantly shifted in energy from those in unstrained VO 2 . That the lattice dynamics remain largely unchanged, while the T c and some of the electronic inter-band transitions differ substantially from the bulk values highlight the role of electronic correlations in driving this metal-insulator phase transition.

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Section: A Sample Strainmentioning

confidence: 73%

Modification of electronic structure in compressively strained vanadium dioxide films

Huffman

Hollingshad

et al. 2015

Phys. Rev. B

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“…The structural transition not only changes the space group from P 4 2 /mnm to P 2 1 /c [28,29], it has severe implications for the electronic bands; hence we have calculated the bandstructure of VO 2 in the rutile and monoclinic (M1) phase by density functional theory (DFT), as well as density of states and optical conductivity using norm-conserving general gradient approximate [30]; this goes beyond the local density approximation that is known not to describe VO 2 properly [31]. In the monoclinic phase a band gap of 0.68 eV occurs, in agreement with the experimental results [12,32,33].…”

Section: Experimental Details and Characterizationmentioning

confidence: 99%

Optical properties of VO2 films at the phase transition: Influence of substrate and electronic correlations

Peterseim

Dressel

Dietrich

et al. 2016

Journal of Applied Physics

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Thin films of VO2 on different substrates, Al2O3 and SiO2/Si, have been prepared and characterized from room temperature up to 360 K. From the band structure in the rutile metallic phase and in the monoclinic insulating phase the optical properties are calculated and compared with reflection measurements as a function of temperatures. Various interband transitions can be assigned and compared with previous speculations. We extract the parameters of the metallic charge carriers that evolve upon crossing the insulator-to-metal phase transition and find effects by the substrate. The effect of electronic correlations becomes obvious at the phase transition.

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“…We use experimental structures [33][34][35] for all calculations. The plane wave kinetic energy cut-off (E cut ) is set at 600 eV, and a 6×6×6 uniform Monkhorst-Pack k-grid is used for the M 1 phase.…”

Section: Computational Detailsmentioning

confidence: 99%

VO2: Orbital competition, magnetism, and phase stability

et al. 2012

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The relative phase stability of VO2 is one of the most fundamental issues concerning the metalinsulator transition in this material but has so far largely unexplored theoretically. We investigate the relative stability of various phases of VO2 using different levels of energy functionals within density functional theory (DFT). It is found that straightforward applications of several popular energy functionals, including the Heyd-Scuseria-Ernzerhof (HSE) hybrid functional, result in a wrong prediction for the ground state of VO2. In particular, although the HSE and DFT+U methods are able to produce a band gap in the M1 phase, they strongly favor the formation of local magnetic moments, a result that clearly disagrees with experiments. We also examine the effect of the occupation and the redistribution of the d derived t2g (i.e., dxz, dyz and d x 2 −y 2 ) orbitals of V atoms on the calculated relative phase stability of VO2. We find that a small change in d-occupation can result in a drastically different theoretical prediction. With the introduction of an orbital-dependent potential, a complete separation between the d x 2 −y 2 derived valence band and dxz and dyz derived conduction bands in the M1 phase is achieved, resulting in a slight redistribution of the d occupation and a more faithful account of the polarization of the t2g orbitals. This slight rearrangement of the d occupation also leads to a relative phase stability of VO2 (including structural and magnetic phases) that agrees well with experiment.

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A Refinement of the Structure of VO2.

Cited by 215 publications

References 0 publications

Modification of electronic structure in compressively strained vanadium dioxide films

Modification of electronic structure in compressively strained vanadium dioxide films

Optical properties of VO2 films at the phase transition: Influence of substrate and electronic correlations

VO2: Orbital competition, magnetism, and phase stability

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