Cluster model calculations of the coherent spectral weight transfer in the bandwidth-controlledCa1−xSrxVO3series

Abstract

We studied the electronic structure of the ${\mathrm{Ca}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}\mathrm{V}{\mathrm{O}}_{3}$ series using a cluster model. The coherent structure is mostly due to a nonlocal coherent screening $(3{d}^{1}\underset{̱}{C})$, whereas the incoherent feature is mainly related to the ligand screening $(3{d}^{1}\underset{̱}{L})$. The increased distortion in the series decreases the V-O-V angle and thus the nonlocal transfer integral ${T}^{*}$. This produces the observed transfer of spectral weight from the coherent to the incoherent structure. A further decrease of ${T}^{*}$ would eventually induce a bandwidth-controlled metal-insulator transition. The weight of the O $2p$ character is considerable and cannot be projected out. This model explains the photon energy dependence of the spectra and the physical properties.