Spin susceptibility scaling in high-temperature superconductors

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Materials

Background:

• The spin response of materials with nested Fermi surfaces is crucial for understanding emergent electronic phases.
• High-temperature superconductors like YBa(2)Cu(3)O(6+x) exhibit complex spin dynamics that are not fully explained by conventional Fermi liquid theory.

Purpose of the Study:

• To investigate the spin response scaling in a nested Fermi surface model.
• To analyze neutron scattering data from YBa(2)Cu(3)O(6+x) for evidence of this scaling.
• To understand the influence of Fermi energy variations on spin susceptibility and its implications for superconductivity.

Main Methods:

• Utilizing a tight-binding energy band model to represent the nested Fermi surface.
• Performing computations of spin susceptibility across various temperatures and frequencies.
• Analyzing neutron scattering data near specific momentum vectors in YBa(2)Cu(3)O(6+x).

Main Results:

• Observed scaling in the spin response (frequency/temperature) within a specific regime near band half-filling.
• Discovered unexpected momentum variations in spin susceptibility at different temperatures and frequencies.
• Found that changes in Fermi energy disrupt scaling, leading to Fermi liquid behavior.

Conclusions:

• The observed scaling and its suppression highlight the delicate balance of electronic states in materials like YBa(2)Cu(3)O(6+x).
• These findings suggest that spin density wave and charge density wave instabilities compete with superconductivity pairing mechanisms.
• Understanding these competing instabilities is essential for designing new superconductors and electronic materials.