On the origin of the split-off conduction bands in V<sub>2</sub>O<sub>5</sub>

Lambrecht, Walter R. L.; Djafari‐Rouhani, Bahram; Vénnik, J.

doi:10.1088/0022-3719/14/32/015

Cited by 39 publications

(31 citation statements)

References 11 publications

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“…38 There are two narrow split-off conduction bands at about 2 eV above the Fermi level and about 0.5 eV below the upper conduction-band range, which have been discussed previously in the literature. 9,11,39 These bands are characterized by rather small dispersion widths corresponding to large effective electron masses and localized band states. The latter are described by dominant V 3d xy character (t 2g symmetry͒ with small O 2 p x,y admixing.…”

Section: B Electronic Structurementioning

confidence: 99%

Geometric and electronic structure of vanadium pentoxide: A density functional bulk and surface study

et al. 1999

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Density-functional theory ͑DFT͒ studies are performed to examine geometric and electronic properties of orthorhombic bulk V 2 O 5 as well as of its ͑010͒ oriented surface. Electronic states, total energies, as well as atom forces ͑used to obtain equilibrium geometries͒ are computed with the ab initio full-potential linear augmented plane wave method. The V 2 O 5 (010) surface is modeled by periodic single layers in a repeated slab geometry, which is justified by the weak electronic interlayer coupling found in the bulk calculations. The electronic structure of the V 2 O 5 (010) single-layer slabs, represented by their valence densities of states ͑DOS͒ and its atom contributions, is compared with results of bulk V 2 O 5 and with previous results obtained by DFT surface cluster studies. The comparison yields good qualitative agreement between the different approaches, which confirms the local nature of interatomic binding in V 2 O 5 . Further, the computed valence DOS is used to interpret recent experimental results from photoemission on V 2 O 5 (010), which suggests that differently coordinated oxygen sites at the surface can be identified in the spectrum. Thus, V 2 O 5 (010) photoemission spectra may be used to monitor the participation of oxygen ions in respective surface reactions.

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Section: B Electronic Structurementioning

confidence: 99%

Geometric and electronic structure of vanadium pentoxide: A density functional bulk and surface study

et al. 1999

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“…Electronically, V 2 O 5 appears at first sight simple because it has a filled oxygen valence band and empty vanadium d-like conduction bands and should thus be a wide gap insulator. However, already in the early band-structure calculations, 3,4 it was found that there is a split-off conduction band, resulting from the d xyorbitals. More precisely, the four V d xy orbitals per cell form four bands, two of which are antisymmetric with respect to the mirror-plane passing through the bridge oxygen.…”

Section: Introductionmentioning

confidence: 99%

Quasiparticle self-consistentGWcalculations of the electronic band structure of bulk and monolayerV2O5

2015

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Quasiparticle self-consistent (QS) GW calculations are performed for bulk and monolayer V2O5. The orbital character of the bands and the bulk monolayer difference at the LDA level are discussed first. We find that the QSGW self-energy overestimates the gap by an unusually large amount. The main reason for this is identified to be the lattice polarization effect: the large LO-TO splittings in this polar material enhance the screening and reduce the screened Coulomb interaction affecting the gap. The effect is estimated to reduce the screened Coulomb interaction and hence the self-energy by a factor 0.38 (for bulk) and brings the calculated optical response functions in fairly good agreement with experiment. For monolayer V2O5, we find that the QSGW gap varies as 1/L with L the size of the spacing between the monolayers in a supercell. This results from the long-range nature of the self-energy Σ = iGW and the similar 1/L behavior of the dielectric screening.

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“…Empty 3d orbitals of vanadium atoms adjacent to a vacancy are able to localize excess electrons. This leads to the formation of localized states in the band gap, 24 which may be involved in the emission observed peaked at 1.70 eV. Actually, enhanced absorption above 2.4 eV has been reported in vacuum annealed V 2 O 5 films and attributed to a decreased oxygen content.…”

Section: Resultsmentioning

confidence: 95%

“…Oxygen vacancies are the most commonly found defects in vanadium pentoxide. 22,24 The structure of V 2 O 5 consists of alternating layers of V + O atoms and O alone, which can be seen by the translation along the c axis. Oxygen vacancies can be easily formed in the O layer between two V -O layers in ͑001͒ type planes.…”

Section: Resultsmentioning

confidence: 99%

Structural and cathodoluminescence assessment of V2O5 nanowires and nanotips grown by thermal deposition

Dı́az-Guerra

Piqueras

2007

Journal of Applied Physics

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V 2 O 5 nanostructures have been grown on 4H-SiC and Si substrates by a thermal deposition method without a catalyst. High aspect ratio nanowires with rectangular cross sections were grown on 4H-SiC. High-resolution transmission electron microscopy observations and cathodoluminescence ͑CL͒ spectroscopy measurements reveal the high crystal quality of the grown nanowires. Deposition on Si substrates leads to the growth of V 2 O 5 platelets or rod-shaped crystals ending in arrays of parallel sharp nanotips with apex radius in the 50 nm range. A CL emission band observed centered at about 1.70 eV in spectra from these nanostructures is tentatively attributed to defect centers involving oxygen vacancies.

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On the origin of the split-off conduction bands in V₂O₅

Cited by 39 publications

References 11 publications

Geometric and electronic structure of vanadium pentoxide: A density functional bulk and surface study

Geometric and electronic structure of vanadium pentoxide: A density functional bulk and surface study

Quasiparticle self-consistentGWcalculations of the electronic band structure of bulk and monolayerV2O5

Structural and cathodoluminescence assessment of V2O5 nanowires and nanotips grown by thermal deposition

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On the origin of the split-off conduction bands in V2O5

Cited by 39 publications

References 11 publications

Geometric and electronic structure of vanadium pentoxide: A density functional bulk and surface study

Geometric and electronic structure of vanadium pentoxide: A density functional bulk and surface study

Quasiparticle self-consistentGWcalculations of the electronic band structure of bulk and monolayerV2O5

Structural and cathodoluminescence assessment of V2O5 nanowires and nanotips grown by thermal deposition

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On the origin of the split-off conduction bands in V₂O₅