Critical Temperatures in the Three-Band Extended Hubbard Model

✍ Scribed by G. Górski; J. Mizia; K. Kucab

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 128 KB
• Volume: 221
• Category: Article
• ISSN: 0370-1972
• DOI: 10.1002/1521-3951(200010)221:2<703::aid-pssb703>3.0.co;2-2

✦ Synopsis

We investigate the three-band extended Hubbard model for the CuO 2 planes of high-temperature superconductors. We consider the limit of U = I on Cu atoms and we include the nearest-neighbor Coulomb repulsion between holes on 2p x,y orbitals of oxygen and holes on 3d x 2 Ày 2 or 3d 3z 2 Àr 2 orbitals of copper (V x and V z respectively, with V x > V z ). This leads to the effective negative nearest-neighbor Coulomb interaction. Numerical analysis of this model reveals the possibility of s-wave and d-wave superconductivity arising from the difference DV = V z ± ± V x . It was shown that the s-wave superconductivity is driven by DV and is opposed by the Coulomb repulsion on oxygen, U p , while the d-wave superconductivity is influenced only by the driving force, DV. This fact would enable existence of the d-wave superconductivity in many high temperature superconducting materials.