Band Structure of Organic-Ion-Intercalated (EMIM)FeSe Superconductor

Area of Science:

• Condensed Matter Physics
• Materials Science
• Solid State Chemistry

Background:

• Superconductivity in iron-based materials is a significant area of research.
• Understanding the electronic structure is crucial for designing new superconductors.
• The role of organic components in inorganic superconductors is not fully understood.

Purpose of the Study:

• To investigate the electronic band structure and Fermi surface of the novel superconductor (EMIM)xFeSe.
• To elucidate the contribution of different atomic orbitals to the electronic states near the Fermi level.
• To determine the influence of the organic cation (EMIM) on the superconducting properties.

Main Methods:

• Utilizing density functional theory (DFT) calculations.
• Employing the generalized gradient approximation (GGA) for exchange-correlation functional.
• Analyzing the band structure and Fermi surface topology.

Main Results:

• The bands near the Fermi level are predominantly derived from Fe-d orbitals.
• No direct contribution from EMIM orbitals to the near-Fermi level states was found.
• The presence of EMIM cations causes a chemical potential shift.
• Small electron pockets emerge on the quasi-two-dimensional Fermi surface.

Conclusions:

• The electronic properties of (EMIM)xFeSe are mainly governed by Fe-d states.
• The organic component plays a crucial indirect role by modulating the electronic structure.
• The formation of electron pockets is a key feature of this superconductor's Fermi surface.