Oxygen p sub z. pi. versus p sub x , sub y Fermi-liquid states in high-T sub c oxides and valence photoemission spectra of Bi sub 2 (Ca, Sr, La) sub 3 C

Journal Article · Sat Mar 31 23:00:00 EST 1990 · Modern Physics Letters B; (USA)

DOI:https://doi.org/10.1142/S0217984990000714· OSTI ID:6427171

Johnson, K H ^[1]

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1. Massachusetts Inst. of Tech., Cambridge, MA (USA)

Recent angle-resolved photoemission studies of the valence-band states of the high-T{sub c} superconductor, Bi{sub 2}(Ca,Sr, La){sub 3}Cu{sub 2}O{sub 8}, have led workers to conclude that the electronic states at the Fermi energy (E{sub F}) have mainly O 2p{sub y} symmetry, while O 2p{sub z}-like states are not allowed by the C{sub 4}({Delta}{sub 5}) symmetry of these states. Nevertheless, a complete projection of the basis functions for the C{sub 4{nu}} symmetry group {Delta}{sub 5} (or E) representation indicates both O 2p{sub x}, 2p{sub y} and O 2p{sub z} orbital contributions at E{sub F}. The O 2p{sub x} and 2p{sub y} components are nonbonding, whereas the O 2p{sub z} orbitals overlap under the influence of significant Cu(d{sub xz,yz}{pi}*)-O (p{sub z}{pi}) antibonding hybridization to form spatially delocalized O(p{sub z}{pi})- O(p{sub z}{pi}) bonding molecular orbitals parallel to the Cu-O x-y (a-b) planes. The doubly-degenerate O(p{sub z}{pi})-O(p{sub z}{pi}) bonds and their associated shallow double-well potentials are the basis for Fermi-liquid character and a dynamic Jahn-Teller mechanism for Cooper pairing first proposed in 1983 and first applied to high-T{sub c} oxides in 1987.

• OSTI ID: 6427171
• Journal Information: Modern Physics Letters B; (USA), Journal Name: Modern Physics Letters B; (USA) Vol. 4:8; ISSN MPLBE; ISSN 0217-9849
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202 -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
426001* -- Engineering-- Superconducting Devices & Circuits-- (1990-)
645300 -- High Energy Physics-- Particle Invariance Principles & Symmetries
656100 -- Condensed Matter Physics-- Superconductivity
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BASIC INTERACTIONS
BISMUTH COMPOUNDS
CHALCOGENIDES
COOPER PAIRS
COPPER COMPOUNDS
COPPER OXIDES
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRONIC STRUCTURE
EMISSION
EMISSION SPECTRA
FERMI INTERACTIONS
HIGH-TC SUPERCONDUCTORS
INTERACTIONS
JAHN-TELLER EFFECT
OXIDES
OXYGEN COMPOUNDS
PHOTOEMISSION
PHYSICAL PROPERTIES
SECONDARY EMISSION
SPECTRA
SUPERCONDUCTIVITY
SUPERCONDUCTORS
SYMMETRY GROUPS
TRANSITION ELEMENT COMPOUNDS
VALENCE
WEAK INTERACTIONS