Robust Charge Density Wave Correlations in Optimally Doped YBa_{2}Cu_{3}O_{y}

Area of Science:

• Condensed Matter Physics
• Materials Science
• Superconductivity

Background:

• Charge density wave (CDW) order is a significant characteristic of high-temperature cuprate superconductors.
• The precise phase boundaries and relationships between CDW order and other phases in cuprates are not fully understood and remain a subject of debate.

Purpose of the Study:

• To investigate the presence and behavior of static charge density wave (CDW) order in YBa2Cu3Oy across different doping levels.
• To determine how factors like doping, quenched disorder, and superconductivity influence the CDW phase boundary.
• To re-evaluate the widely accepted critical doping concentration (p*) for the end of the pseudogap phase.

Main Methods:

• Nuclear Magnetic Resonance (NMR) spectroscopy was employed to probe the electronic properties of YBa2Cu3Oy samples.
• NMR measurements were conducted on samples with varying doping levels, including optimally doped (p=0.165) and overdoped (p=0.184) regimes.

Main Results:

• Short-range static CDW order was found to be robust at optimal doping (p=0.165), with properties similar to underdoped samples (p≃0.11).
• No static CDW order was detected in an overdoped sample (p=0.184) down to the superconducting transition temperature (Tc), although weak CDW order may emerge below Tc.
• The study suggests that quenched disorder and competition with superconductivity affect the observed CDW phase boundary, potentially leading to an underestimation of its intrinsic doping range.

Conclusions:

• The findings indicate that static CDW order is more persistent with doping than previously thought.
• The results challenge the notion that the CDW phase boundary is located below p*≃0.19 in YBa2Cu3Oy.
• A more comprehensive understanding of the interplay between CDW order, superconductivity, and disorder is crucial for cuprate physics.