Fehrenbacher-Rice model

The main shortcoming of the original Fehrenbacher-Rice (1993b) model was its inability to describe the different rate of suppression with the different rare-earth hosts. The modification in the Liechtenstein-Mazin (1995) model, derived from LDA+U calculation, explained this phenomenon naturally. Unlike the Fehrenbacher-Rice model, the LDA+U treatment expresses the FR state in a band form. The position of the band... 

The Fehrenbacher and Rice model had clear advantages over the other models put forward, however it had a number of difficulties. Some of these problems have been addressed, and in the remainder of this section we shall concentrate on this model and its more modern versions. 

Let us first set /pd to zero. This corresponds to the original Fehrenbacher-Rice (1993b) model. Dispersion of the oxygen p r states is completely neglected an isolated Pr impurity forms a localized antibonding state, shifted up with respect to the bare O p level by... 

Fig. 12. Tight-binding orbitals corresponding to the Fehrenbacher-Rice (1993b) model (projected onto the jr-p-plane). The Pr z(x -y ) orbital is in the center.

One striking fact is that the ridge, predicted for the metallic PrBa2Cu307 (Singh 1994), is observed by 2D-ACAR, despite the insulating behavior of the crystal. The existence of the Fermi surface in this case is supported by the model of Fehrenbacher and Rice (1993). 

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