Optical studies of gap, exchange, and hopping energies in the insulating cuprates

Journal Article · Sat Dec 01 04:00:00 EST 1990 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.42.10785· OSTI ID:5941316

Cooper, S L; Thomas, G A; Millis, A J; Sulewski, P E; Orenstein, J; Rapkine, D H; Cheong, S; Trevor, P L ^[1]

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1. AT T Bell Laboratories, Murray Hill, NJ (USA)

We have measured the insulating energy gap {Delta} and the exchange interaction {ital J} in a series of cuprate crystals, including {ital T}{prime}-phase {ital M}{sub 2}CuO{sub 4} ({ital M}=Pr, Nd, Sm, Eu, and Gd), {ital T}{sup *}-phase La,Tb,Sr{sub 2}CuO{sub 4}, and {ital T}-phase La{sub 2}CuO{sub 4}. We find that the energy gap scales predominantly with the in-plane Cu-O distance, scaling as {delta} log{Delta}/ {delta} log{ital d}{similar to}{minus}6. Furthermore, contrary to simple expectations, the energy gap increases with decreasing Cu-O distance, suggesting that Coulomb and other repulsive energies dominate the effects of band hybridization. Using a three-band Hubbard-model expression, our studies of {Delta} and {ital J} in the cuprates allow us to estimate that the hopping energy {ital t} scales with Cu-O distance as {delta} log{ital t}/{delta} log{ital d}{similar to}{minus}4.

• OSTI ID: 5941316
• Journal Information: Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 42:16; ISSN PRBMD; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
BAND THEORY
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
ENERGY GAP
EUROPIUM COMPOUNDS
EUROPIUM OXIDES
EXCHANGE INTERACTIONS
GADOLINIUM COMPOUNDS
GADOLINIUM OXIDES
HIGH-TC SUPERCONDUCTORS
INTERACTIONS
LANTHANUM COMPOUNDS
LANTHANUM OXIDES
NEODYMIUM COMPOUNDS
NEODYMIUM OXIDES
OPTICAL PROPERTIES
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
PRASEODYMIUM COMPOUNDS
PRASEODYMIUM OXIDES
RAMAN SPECTRA
RARE EARTH COMPOUNDS
REFLECTIVITY
SAMARIUM COMPOUNDS
SAMARIUM OXIDES
SPECTRA
SUPERCONDUCTORS
SURFACE PROPERTIES
TERBIUM COMPOUNDS
TERBIUM OXIDES
TRANSITION ELEMENT COMPOUNDS