Soft fermi surfaces and breakdown of Fermi-liquid behavior

Area of Science:

• Condensed matter physics
• Quantum materials
• Many-body physics

Background:

• Electron-electron interactions can significantly alter electronic properties.
• Pomeranchuk instabilities involve Fermi surface deformations breaking lattice symmetry.
• Anisotropic perturbations near these instabilities enhance collective fluctuations.

Purpose of the Study:

• Investigate the impact of critical Fermi surface fluctuations on single-particle excitations.
• Analyze the behavior of Fermi-liquid theory near a d-wave Pomeranchuk instability.
• Determine the conditions under which Fermi-liquid behavior is preserved or destroyed.

Main Methods:

• Theoretical analysis of electron-electron interactions in two dimensions.
• Study of critical fluctuations near a d-wave Pomeranchuk instability.
• Calculation of single-particle excitation decay rates.

Main Results:

• Critical Fermi surface fluctuations induce large anisotropic decay rates.
• Fermi-liquid behavior is destroyed over most of the Fermi surface.
• An exception to the destroyed Fermi-liquid behavior is observed at the Brillouin zone diagonal.

Conclusions:

• The study highlights the breakdown of Fermi-liquid theory due to critical fluctuations.
• Anisotropic decay rates are a key consequence of Pomeranchuk instabilities.
• Understanding these effects is crucial for predicting properties of strongly correlated electron systems.