Possible cluster pairing correlation in the checkerboard Hubbard model: a quantum Monte Carlo study

Area of Science:

• Condensed Matter Physics
• Quantum Materials
• Computational Physics

Background:

• The checkerboard Hubbard model is a theoretical framework for studying strongly correlated electron systems.
• Understanding pairing correlations is crucial for discovering novel quantum phases.
• Inhomogeneous parameters can significantly alter material properties.

Purpose of the Study:

• To investigate the impact of inhomogeneous nearest-neighbor hopping on pairing correlations in a low-doped checkerboard Hubbard model.
• To determine if inhomogeneity can be used to enhance and control pairing phenomena.
• To explore the relationship between pairing correlation enhancement and Fermi surface structure.

Main Methods:

• Application of the constrained-path quantum Monte Carlo (CP-QMC) method.
• Simulation of the checkerboard Hubbard model with varying degrees of inhomogeneous hopping.
• Analysis of pairing correlation functions and their spatial extent.

Main Results:

• Inhomogeneous hopping was found to enhance pairing correlations among plaquette clusters.
• A clear maximum in pairing correlation was observed at a specific level of inhomogeneity.
• The strongest long-range behavior of cluster pairing correlation occurred at this optimal inhomogeneity.
• This enhancement may be linked to a transition in the Fermi surface structure.

Conclusions:

• Inhomogeneous nearest-neighbor hopping is an effective tool for tailoring pairing correlations in the checkerboard Hubbard model.
• The findings suggest potential pathways for designing materials with enhanced superconducting or other pairing-related properties.
• Further investigation into the Fermi surface transitions associated with optimal inhomogeneity is warranted.