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Updated: Jul 5, 2025
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Published on: August 2, 2019
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Bands renormalization and superconductivity in the strongly correlated Hubbard model using composite operators
L Haurie1, M Grandadam2, E Pangburn1
1Institut de Physique Théorique, Université Paris Saclay, CEA CNRS, Orme des Merisiers, 91190 Gif-sur-Yvette Cedex, France.
Summary
This study analyzes the Hubbard model using the composite operator method (COM), revealing superconductivity arises from the Van Hove singularity. Results are compared with ARPES measurements on cuprates.
Area of Science:
- Condensed Matter Physics
- Quantum Many-Body Theory
Background:
- The repulsive Hubbard model is crucial for understanding strongly correlated electron systems.
- Investigating higher-order hoppings is essential for realistic material simulations.
Purpose of the Study:
- To analyze the strongly correlated repulsive Hubbard model using the composite operator method (COM).
- To investigate the impact of nearest-neighbor hoppings up to fourth order on a square lattice.
- To study the emergence of superconductivity and its relation to the Van Hove singularity.
Main Methods:
- Application of the composite operator method (COM).
- Utilizing two sets of self-consistent equations: one enforcing the Pauli principle, another using Roth's decoupling scheme for correlations.
- Extraction of three distinct solutions (COM1, COM2, Roth decoupling).
Main Results:
- Three distinct solutions were identified based on the applied principles.
- The validity of particle-hole symmetry and the Luttinger theorem was assessed for each solution.
- Superconductivity was found to be induced by the Van Hove singularity.
Conclusions:
- The composite operator method provides insights into strongly correlated systems.
- Superconductivity in this model is linked to the Van Hove singularity.
- The study offers a comparison with experimental ARPES measurements on cuprates.
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