Strange Metal and Superconductor in the Two-Dimensional Yukawa-Sachdev-Ye-Kitaev Model

Area of Science:

• Condensed Matter Physics
• Quantum Materials
• Statistical Mechanics

Background:

• The two-dimensional Yukawa-Sachdev-Ye-Kitaev (2D-YSYK) model describes quantum phase transitions in metals with quenched disorder.
• It features a Fermi surface interacting with a scalar field via spatially random Yukawa interactions.

Purpose of the Study:

• To provide full numerical solutions for the 2D-YSYK model.
• To analyze the model in both normal and superconducting states.
• To compare results with experimental observations in cuprates.

Main Methods:

• Self-consistent disorder-averaged analysis.
• Full numerical solutions of the 2D-YSYK model.
• Calculation of electronic spectral functions, conductivity, and superfluid stiffness.

Main Results:

• The model successfully reproduces key aspects of cuprate observations.
• A regime was identified where zero-temperature superfluid stiffness increases as the superconducting critical temperature decreases.
• Electronic spectral functions and frequency-dependent conductivity were obtained.

Conclusions:

• The 2D-YSYK model offers a universal framework for understanding quantum criticality in disordered metals.
• The findings align with experimental data from cuprate superconductors.
• The model predicts a specific relationship between superfluid stiffness and critical temperature relevant to cuprates.