Evolution of the spectral weight in the Mott-Hubbard series SrVO3-CaVO3-LaVO3-YVO3

We studied the Mott-Hubbard series SrVO(3)-CaVO(3)-LaVO(3)-YVO(3) with high-energy photoemission. The features in the experimental spectra were interpreted using cluster model calculations. The valence-band photoemission results show very interesting trends across the Mott-Hubbard series: (i) From SrVO(3) to CaVO(3), the spectral weight is transferred from the coherent to the incoherent feature. (ii) From CaVO(3) to LaVO(3), the coherent structure disappears, opening the insulating band gap. (iii) Finally, from LaVO(3) to YVO(3), the bandwidth of the remaining incoherent feature further decreases. There is also a considerable V 3d spectral weight contribution mixed in the O 2p band region in all cases. These results suggest that the O 2p states play an important role in the Mott-Hubbard transition. Some of the changes in the spectra are unexpected and cannot be explained by the current Mott-Hubbard theories. The calculation reproduces not only the coherent and incoherent structures in the V 3d band but also the main features in the O 2p band. In addition, the same model explains the charge-transfer satellites observed in the V 2p core-level spectra.