High-Temperature Superconductivity from Finite-Range Attractive Interaction

Area of Science:

• Condensed Matter Physics
• Quantum Materials
• Superconductivity Theory

Background:

• Conventional BCS theory describes superconductivity via attractive contact interactions.
• Long-range attractive interactions are not fully explored within BCS framework.
• Understanding deviations from BCS is crucial for novel superconducting materials.

Purpose of the Study:

• To investigate the impact of finite-range attractive interactions on Fermi liquids.
• To explore the conditions for superconductivity beyond standard BCS theory.
• To analyze the resulting phenomena, such as quantum criticality and critical temperature dependence.

Main Methods:

• Theoretical analysis of D-dimensional interacting Fermi liquids.
• Examination of pair susceptibility under finite-range interactions.
• Modeling superconductivity in layered quasi-two-dimensional materials with phonon-mediated interactions.

Main Results:

• Finite-range attractive interactions (R_s >> λ_F) do not induce a superconducting gap, contrary to BCS predictions.
• Pair susceptibility exhibits a power-law singularity, indicating quantum critical behavior without long-range order.
• Superconductivity is stabilized by introducing a short-range attractive interaction.
• A dome-shaped critical temperature (Tc) versus doping is observed, with a suppressed isotope effect and weak dependence on interaction range.

Conclusions:

• The study reveals limitations of BCS theory for finite-range interactions.
• Quantum criticality without long-range order is a key feature of these systems.
• The findings offer insights into mechanisms relevant to high-temperature superconductors.