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Subband filling and Mott transition in Ca_{2-x}Sr_xRuO_4

A. Liebsch·H. Ishida
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Abstract

A new concept is proposed for the paramagnetic metal insulator transition in the layer perovskite Ca_{2-x}Sr_xRuO_4. Whereas the pure Sr compound is metallic up to very large Coulomb energies due to strong orbital fluctuations, structural changes induced by doping with Ca give rise to a interorbital charge transfer which makes the material extremely sensitive to local correlations. Using dynamical mean field theory based on finite temperature multi-band exact diagonalization it is shown that the combination of crystal field splitting and onsite Coulomb interactions leads to complete filling of the d_xy band and to a Mott transition in the half-filled d_xz,yz bands.

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A. Liebsch, H. Ishida. 2006-12-21. Subband filling and Mott transition in Ca_{2-x}Sr_xRuO_4. https://doi.org/10.1103/physrevlett.98.216403

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