Doping-dependent charge order correlations in electron-doped cuprates

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Materials

Background:

• Understanding charge order (CO) is crucial for high-temperature cuprate superconductors.
• Similar CO forms in hole- and electron-doped cuprates prompt investigation into universal CO phenomena.
• The relationship between CO and other key phenomena (pseudogap, antiferromagnetism, superconductivity) remains a central question.

Purpose of the Study:

• To investigate charge order (CO) correlations in electron-doped cuprates (La2-x Cex CuO4 and Nd2-x Cex CuO4).
• To determine the relationship between CO and antiferromagnetism, pseudogap, and superconductivity in these materials.
• To ascertain the universality of CO phenomenology across different cuprate types.

Main Methods:

• Resonant x-ray scattering was employed to measure CO correlations.
• Detailed measurements were conducted on Nd2-x Cex CuO4 across various doping levels (x = 0.059 to 0.166).
• CO behavior was examined relative to superconducting transition temperature and in the presence of a magnetic field.

Main Results:

• Charge order (CO) was confirmed in electron-doped Nd2-x Cex CuO4 within a specific doping range.
• The CO wave vector correlates with Fermi surface segments and a phonon anomaly near optimal doping.
• CO onset temperature is highest between x = 0.106 and 0.166, decreasing at lower doping, and is insensitive to superconductivity.

Conclusions:

• Charge order (CO) in electron-doped cuprates is not intrinsically tied to antiferromagnetism or the pseudogap.
• Material-dependent factors dictate the strength and prevalence of CO correlations.
• The ability of CO to compete for the ground state in cuprates is influenced by these material-specific details.