Relation of extended Van Hove singularities to high-temperature superconductivity within strong-coupling theory
- Department of Physics and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637 (United States)
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)
Recent angle-resolved photoemission (ARPES) experiments have indicated that the electronic dispersion in some of the cuprates possesses an extended saddle point near the Fermi level which gives rise to a density of states that diverges like a power law instead of the weaker logarithmic divergence usually considered. We investigate whether this strong singularity can give rise to high transition temperatures by computing the critical temperature [ital T][sub [ital c]] and isotope effect coefficient [alpha] within a strong-coupling Eliashberg theory which accounts for the full energy variation of the density of states. Using band structures extracted from ARPES measurements, we demonstrate that, while the weak-coupling solutions suggest a strong influence of the strength of the Van Hove singularity on [ital T][sub [ital c]] and [alpha], strong-coupling solutions show less sensitivity to the singularity strength and do not support the hypothesis that band-structure effects alone can account for either the large [ital T][sub [ital c]]'s or the different [ital T][sub [ital c]]'s within the copper oxide family. This conclusion is supported when our results are plotted as a function of the physically relevant self-consistent coupling constant, which shows universal behavior at very strong coupling.
- DOE Contract Number:
- W-31-109-ENG-38
- OSTI ID:
- 7202924
- Journal Information:
- Physical Review, B: Condensed Matter; (United States), Vol. 50:13; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
HIGH-TC SUPERCONDUCTORS
ELECTRONIC STRUCTURE
GORKOV-ELIASHBERG THEORY
ISOTOPE EFFECTS
SINGULARITY
STRONG-COUPLING MODEL
TRANSITION TEMPERATURE
MATHEMATICAL MODELS
PARTICLE MODELS
PHYSICAL PROPERTIES
SUPERCONDUCTORS
THERMODYNAMIC PROPERTIES
665411* - Basic Superconductivity Studies- (1992-)