Fermi surfaces, fermi liquids, and high-temperature superconductors

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Mechanics

Background:

• High-temperature superconductivity remains a significant challenge in condensed matter physics.
• Existing theories struggle to reconcile with emerging experimental data.

Purpose of the Study:

• To review recent experimental findings that constrain theories of high-temperature superconductivity.
• To highlight the importance of the Fermi surface in understanding metallic phases.
• To identify key areas for future research into the superconducting pairing mechanism.

Main Methods:

• Review of experimental results from angle-resolved photoemission spectroscopy.
• Analysis of positron annihilation data.
• Interpretation of de Haas-van Alphen experiments.

Main Results:

• Experimental observations of a Fermi surface are consistent across multiple methods and groups.
• Data align with band theory predictions, challenging the 'doped insulator' model for metallic phases.
• Low-energy excitations (quasiparticles) exhibit strong interactions with atomic, magnetic, and charge fluctuations.

Conclusions:

• The existence of a Fermi surface necessitates realistic theories focusing on metallic phases.
• Metallic phases of high-temperature superconductors are unlikely to be simple doped insulators.
• Understanding quasiparticle interactions is crucial for developing a microscopic theory of superconductivity.