Hidden Fermionic Excitation Boosting High-Temperature Superconductivity in Cuprates

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Mechanics

Background:

• Cuprate models are crucial for understanding high-temperature superconductivity.
• The two-dimensional Hubbard model is a fundamental microscopic model for correlated electrons.
• Understanding the interplay between pseudogap and superconductivity remains a key challenge.

Purpose of the Study:

• To investigate the dynamics of the two-dimensional Hubbard model using advanced theoretical methods.
• To elucidate the microscopic mechanisms behind the pseudogap and superconductivity in cuprates.
• To explore the role of strong electronic correlations and emergent phenomena.

Main Methods:

• Utilized a cluster extension of the dynamical mean-field theory (DMFT).
• Analyzed frequency-dependent self-energies to understand electronic behavior.
• Investigated quasiparticle hybridization with emergent fermionic excitations.

Main Results:

• Identified a nontrivial structure in frequency-dependent self-energies.
• Revealed an unprecedented interplay between the pseudogap and superconductivity.
• Demonstrated that quasiparticles hybridize with 'hidden' fermionic excitations, explaining these phenomena.

Conclusions:

• The 'hidden fermion' enhances superconductivity through a novel mechanism.
• This hidden fermion is responsible for the normal-state pseudogap.
• This theoretical framework may resolve outstanding experimental puzzles in cuprate superconductors.