Cluster model and band structure calculations of ${\mathrm{V}}_2{\mathrm{O}}_5$: Reduced ${\mathrm{V}}^{5+}$ symmetry and many-body effects

We studied the electronic structure of the ${\mathrm{V}}_2{\mathrm{O}}_5$ compound using cluster model calculations. The calculation included the reduced ${\mathrm{V}}^{5+}$ symmetry and the strong $\mathrm{V}3d–\mathrm{O}2p$ covalence effects. The many-body effects are taken into account using the configuration interaction method. The ground state of ${\mathrm{V}}_2{\mathrm{O}}_5$ is highly covalent and dominated by the $3d^1\underset{̱}{L}$ $\left({}^{1}A_1\right)$ configuration, where $\underset{̱}{L}$ denotes a ligand hole. The ${\mathrm{V}}_2{\mathrm{O}}_5$ material is in the charge-transfer regime and the band gap is due to $p\text{−}d$ transitions. The first removal state is given by the $3d^0\underset{̱}{L}$ $\left({}^{2}A_1\right)$ configuration, and the first addition state is formed by the $3d^1$ $\left({}^{2}E\right)$ configuration. The results of the cluster model are in good agreement with band structure calculations. The calculation results are also in good agreement with photoemission and x-ray absorption spectra. The $\mathrm{V}2p$ core-level spectra exhibit many-body effects despite the nominal $3d^0$ occupancy. These effects and the reduced ${\mathrm{V}}^{5+}$ symmetry are crucial to describe the electronic structure of ${\mathrm{V}}_2{\mathrm{O}}_5$.

Figure 1

Splitting of the transition metal $d$ levels in ${\mathrm{O}}_h$ and $C_{4v}$ symmetries.

Figure 2

(Color online) The spectral weight of ${\mathrm{V}}_2{\mathrm{O}}_5$ from the cluster model compared to the density of states from the band structure calculation.

Figure 3

Photoemission spectrum of ${\mathrm{V}}_2{\mathrm{O}}_5$ taken at $50\mathrm{eV}$ compared to the total DOS (band structure) and the spectral weight (cluster model).

Figure 4

$\mathrm{O}1s$ x-ray absorption spectrum of ${\mathrm{V}}_2{\mathrm{O}}_5$ compared to the $\mathrm{O}2p$ DOS (band structure) and the $\mathrm{O}2p$ spectral weight (cluster model).

Figure 5

$\mathrm{V}2p$ x-ray photoelectron spectrum of ${\mathrm{V}}_2{\mathrm{O}}_5$ compared to the cluster model spectral weight projected into the main final state configurations.

Figure 6

$\mathrm{V}2p$ x-ray absorption spectrum of ${\mathrm{V}}_2{\mathrm{O}}_5$ compared to the cluster model spectral weight projected into the main final state configurations.