Strange Metals as Ersatz Fermi Liquids

Area of Science:

• Correlated electron physics
• Quantum materials science
• Condensed matter theory

Background:

• Understanding strange non-Fermi liquid metals is a fundamental challenge in correlated electron physics.
• These materials exhibit unusual properties, notably resistivity linear with temperature (T).

Purpose of the Study:

• To determine the requirements for achieving non-Fermi liquid physics down to zero temperature in translationally invariant metals.
• To investigate the implications of frequency-dependent conductivity satisfying omega/T scaling.

Main Methods:

• Theoretical analysis combining existing arguments on 'ersatz Fermi liquids' with new insights.
• Investigation of the low-energy fixed point physics governing T-linear resistivity.
• Analysis of symmetry properties and emergent conserved quantities.

Main Results:

• Demonstrated that T-linear resistivity originates from the intrinsic physics of the low-energy fixed point under specific conditions.
• Showed the necessary existence of a diverging susceptibility for a specific type of operator (odd under inversion and time reversal, zero crystal momentum).
• Identified potential experimental consequences and loopholes.

Conclusions:

• Established a theoretical framework for understanding non-Fermi liquid behavior in translationally invariant metals.
• Highlighted the crucial role of symmetry and emergent quantities in these exotic states.
• Opened avenues for further experimental investigation into quantum materials.