Electronic structures of high-{Tc} superconductors LnBa{sub 2}Cu{sub 3}O{sub 7} (Ln = Pr, Nd, Gd, Dy)

Journal Article · Tue Oct 05 04:00:00 EDT 1993 · International Journal of Quantum Chemistry

OSTI ID:83261

Li, Ming ^[1]

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1. Southwest China Normal Univ., Chongqing (China)

In the present paper, the electronic energy-band structures of the LnBa{sub 2}Cu{sub 3}O{sub 7} (Ln = Pr, Nd, Gd, and Dy) were investigated employing the EHMO approach based on the tight-binding method. The results show that the substitution of Nd, Gd, and Dy for Y in YBa{sub 2}Cu{sub 3}O{sub 7} complicates the shape of the Fermi surface and results in an increase in the number of energy bands crossing the Fermi level, Ef. Compared with those of YBa{sub 2}Cu{sub 3}O{sub 7}, the electronic densities of states at Ef, N(Ef), for NdBa{sub 2}Cu{sub 3}O{sub 7}, GdBa{sub 2}Cu{sub 3}O{sub 7}, and DyBa{sub 2}Cu{sub 3}O{sub 7} increase greatly, whereas those of PrBA{sub 2}Cu{sub 3}O{sub 7} are very small. The results given by the present calculations explain why the substitution of Nd, Gd, and Dy for Y in YBa{sub 2}Cu{sub 3}O{sub 7} can still maintain the high transition temperature {Tc}, while PrBa{sub 2}Cu{sub 3}O{sub 7} is a semiconductor rather than a superconductor.

• OSTI ID: 83261
• Journal Information: International Journal of Quantum Chemistry, Journal Name: International Journal of Quantum Chemistry Journal Issue: 1 Vol. 48; ISSN IJQCB2; ISSN 0020-7608
• Country of Publication: United States
• Language: English

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