Low-energy microscopic models for iron-based superconductors: a review

Area of Science:

• Condensed Matter Physics
• Materials Science

Background:

• Iron-based superconductors exhibit complex normal-state and superconducting properties.
• Effective low-energy models are crucial for understanding these metallic systems near the Fermi level.
• Multi-orbital nature and strong electronic correlations (Hubbard and Hund interactions) complicate modeling.

Purpose of the Study:

• To review and analyze minimal models for iron-based superconductors.
• To elucidate universal features and the interplay of different orders.
• To compare theoretical models with experimental observations.

Main Methods:

• Review of orbital-basis and band-basis minimal models.
• Analysis of renormalization group studies on advanced band-basis models.
• Incorporation of orbital composition, symmetries, and glide-plane symmetry.

Main Results:

• Orbital-basis models offer qualitative insights but are limited beyond mean-field.
• Band-basis models allow beyond-mean-field investigations of competing orders.
• Recent models successfully integrate orbital details and symmetries, explaining experimental results.

Conclusions:

• Minimal models are essential for understanding iron-based superconductors.
• Advanced models incorporating orbital composition and symmetries are vital.
• These models reveal the intricate interplay between superconductivity, magnetism, and orbital order.