Atomic-scale electronic structure of the cuprate pair density wave state coexisting with superconductivity

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Materials

Background:

• Cuprates exhibit d-wave high-temperature superconductivity.
• Theoretical interest exists in a coexisting pair density wave (PDW) state within cuprates.

Purpose of the Study:

• To model a pair density wave (PDW) state coexisting with d-wave superconductivity (DSC) in cuprates.
• To compare theoretical predictions with experimental data from Bi2Sr2CaCu2O8.

Main Methods:

• Utilized strong-coupling mean-field theory for cuprates.
• Modeled an eight-unit-cell periodic, d-symmetry form factor PDW + DSC state.
• Predicted atomically resolved Bogoliubov quasiparticle states at the BiO surface.
• Compared predictions with spectroscopic imaging scanning tunneling microscopy (STM) experiments.

Main Results:

• The PDW + DSC model accurately predicts intraunit-cell structure and modulations of Bogoliubov quasiparticle states.
• Model predicts modulations in coherence peak energy and Bogoliubov quasiparticle interference patterns.
• Experimental consistency indicates the presence of a PDW + DSC state in lightly hole-doped Bi2Sr2CaCu2O8.
• The PDW + DSC state becomes unstable to a pure DSC state at a critical hole density (p*).

Conclusions:

• The study provides strong evidence for a coexisting PDW + DSC state in Bi2Sr2CaCu2O8.
• The observed charge modulations are a consequence of the PDW state.
• The antinodal pseudogap is attributed to the PDW state.
• The critical point at p* ≈ 19% is linked to the disappearance of the PDW state.