Comment on quantitative model for the superconductivity suppression in R(sub 1-x)Pr(sub x)Ba(sub 2)Cu(sub 3)O(sub 7) with different rare earths

摘要

In a recent letter, a model for the electronic structure of R(sub 1-x)Pr(sub x)Ba(sub 2)Cu(sub 3)O(sub 7), based on the LDA + U scheme was proposed. The T(sub c) suppression by Pr substitution was argued to be due to the transfer of holes from the superconducting CuO pd(sigma) to a dispersive pf(pi) band formed by O2p(sub (pi)) and Pr 4f orbitals. The insulating nature of PrBa(sub 2)Cu(sub 3)O(sub 7) was ascribed to disorder from Ba atoms on the Pr sites. The ac conductivity of the above compound is discussed.