Doping site identification in 112 iron pnictides through a first-principles core-electron spectroscopic study

Area of Science:

• Condensed Matter Physics
• Materials Science
• Solid State Chemistry

Background:

• Iron-based superconductors, particularly the 112 materials, feature unique crystal structures with Fe-As planes and an additional As zigzag chain.
• Understanding the role of different atomic sites, especially arsenic, is crucial for tuning superconducting properties.

Purpose of the Study:

• To investigate the impact of doping on the superconducting transition temperature in iron-based 112 materials.
• To theoretically analyze the electronic structure and spectroscopic properties related to arsenic atoms in these superconductors.
• To provide insights for experimental identification of different arsenic sites.

Main Methods:

• Density Functional Theory (DFT) based first-principles calculations.
• Core-electron spectroscopic studies, specifically As K-edge absorption spectra.
• Analysis of site-projected density of states (DOS).

Main Results:

• Doping the As site within the zigzag chain by Antimony (Sb) enhances the superconducting transition temperature.
• Calculations show an increased density of states at the Fermi level upon doping the chain-As site.
• Theoretically computed As K-edge absorption spectra reveal distinct differences for various As atoms, sensitive to the core-hole effect.

Conclusions:

• The As site in the zigzag chain plays a critical role in the superconductivity of 112 materials.
• Sb doping on this specific As site is a viable strategy to enhance superconducting properties.
• As K-edge absorption spectra, considering the core-hole effect, can be a powerful experimental tool for distinguishing arsenic sites.