Atomically-resolved interlayer charge ordering and its interplay with superconductivity in YBa₂Cu₃O_6.81

Area of Science:

• Condensed Matter Physics
• Materials Science

Background:

• High-temperature cuprates feature superconductive and competing charge order (CO) phases.
• Understanding the interplay between CO and superconductivity is crucial for elucidating superconductivity mechanisms.

Purpose of the Study:

• To directly image the spatial relationship between charge order and superconductivity in YBa2Cu3O6.81 at atomic resolution.
• To investigate interlayer coupling effects in both charge order and superconductive states.

Main Methods:

• Cryogenic cleavage of YBa2Cu3O6.81 samples.
• Cross-sectional scanning tunneling microscopy/spectroscopy (STM/STS) for atomic-scale imaging.

Main Results:

• Charge order nanodomains are observed embedded within the superconductive phase.
• A proximity-like boundary region shows mutual suppression of charge order and superconductivity.
• Superconductivity and charge order coexist on both CuO chain and plane layers, indicating inter-layer coupling.

Conclusions:

• Charge order nanodomains influence superconductivity through proximity effects.
• Interlayer carrier transport and density of states mixing are significant.
• Coulomb repulsion likely dominates Josephson tunneling between layers in the charge ordered state.