Valence-band electronic structure of ${\text{V}}_2{\text{O}}_3$: Identification of V and O bands

We present a comprehensive study of the photon energy dependence of the valence band photoemission yield in the prototype Mott-Hubbard oxide ${\text{V}}_2{\text{O}}_3$. The analysis of our experimental results, covering an extended photon energy range (20–6000 eV) and combined with GW calculations, allows us to identify the nature of the orbitals contributing to the total spectral weight at different binding energies, and in particular to locate the $\text{V}4s$ states at about 8 eV binding energy. From this comparative analysis, we conclude that the intensity of the quasiparticle photoemission peak, observed close to the Fermi level in the paramagnetic metallic phase upon increasing photon energy, does not have a significant correlation with the intensity variation in the $\text{O}2p$ and $\text{V}3d$ yield, thus, confirming that bulk sensitivity is an essential requirement for the detection of this coherent low-energy excitation.

Figure 1

(Color online) Experimental valence band PES spectra of ${\text{V}}_2{\text{O}}_3$, normalized to the bottom of the incoherent spectral region at about $-3\text{eV}$ binding energy.

Figure 2

(Color online) Measured valence-band spectra compared to the total weighted DOS from GW calculations. The weighting has been obtained by multiplying partial $s,p,d$ DOS’s (see Table ). In the insets, the weighted DOS before convolution with a lorentzian broadening and with a Fermi energy distribution.

Figure 3

(Color online) Direct comparison of selected pairs of experimental spectra taken at different photon energies. In the inset, the details of the QP region are shown for the two spectra at 900 and 5934 eV.

Figure 4

(Color online) Calculated spectra for different photon energies (19, 37, and 86 eV) using Eq. (1), including (continuous curves) or neglecting (dotted curves) matrix elements effects. The dashed curve (same for all photon energies) is the DOS.