FeSe
Iron selenide · Iron(II) selenide
FeSe is a thermodynamically stable, metallic iron-chalcogenide compound widely studied for its superconducting properties.
About Iron selenide
FeSe is a prominent member of the iron-based superconductor family, characterized by its metallic electronic structure and inherent thermodynamic stability. As a material that resides on the convex hull, it serves as a foundational subject for researchers investigating the complex interplay between magnetism and superconductivity.
Its importance stems from its relatively simple crystal structure compared to more complex iron-pnictide counterparts. This simplicity allows for precise experimental control and theoretical modeling, making it a vital platform for studying the mechanisms that drive high-temperature superconductivity in metallic systems.
Key Properties
Cross-validated computational properties for Iron selenide, aggregated across 6 databases.
Band GapEnergy needed to move an electron from the valence band to the conduction band. Lower or zero values tend to behave more metallic; larger gaps are more insulating or semiconducting.
Energy Above HullThermodynamic distance from the most stable set of competing phases. 0 eV/atom is on the convex hull; small positive values may still be experimentally accessible.
StabilityA plain-language summary of the best reported energy-above-hull result. It reflects whether the lowest-energy structure is on, near, or far from the stability hull.
StructuresCount of reported calculated crystal structures for this formula, including alternate polymorphs, source databases, and observed space groups.
Cross-Source DFT Agreement
How well independent DFT databases agree on the thermodynamics of FeSe. Tight agreement means computed properties can be trusted without re-running calculations.
Agreement ScoreA normalized confidence score summarizing how closely independent DFT databases agree. Higher scores mean tighter cross-source agreement.
Hull SpreadDifference between the highest and lowest energy-above-hull values reported by comparable sources. Smaller spread means less thermodynamic disagreement.
Sources ComparedNumber and names of computational sources with comparable entries for this formula.
Space Group ConsensusWhether independent sources predict the same crystal symmetry for the lowest-energy structure.
Reported Structures
Lowest-energy structures reported for FeSe, ranked by energy above hull.
| Space GroupSymmetry classification of the crystal arrangement. The number is the international space-group index. | Crystal SystemBroad lattice family, such as cubic, tetragonal, monoclinic, or triclinic, derived from unit-cell symmetry. | Band Gap (eV)Electronic gap calculated for this specific reported structure, measured in electronvolts. | E above hull (eV/atom)Thermodynamic distance from the convex hull for this structure, normalized per atom. Lower is generally more stable. | E/atom (eV)Computed total energy normalized per atom. Use energy above hull, not this value alone, when comparing stability. | Density (g/cm³)Mass per relaxed crystal volume, reported in grams per cubic centimeter. |
|---|---|---|---|---|---|
| P4/nmm (No. 129) | tetragonal | 0.00 | 0.0000 | -6.491 | 4.94 |
| P63/mmc (No. 194) | hexagonal | 0.00 | 0.1908 | -6.300 | 7.10 |
| Pnma (No. 62) | orthorhombic | 0.00 | 0.2073 | -6.284 | 7.13 |
| Cmcm (No. 63) | orthorhombic | 0.00 | 0.2506 | -6.240 | 6.58 |
| Pnma (No. 62) | orthorhombic | 0.00 | 0.2533 | -6.238 | 6.58 |
| Pnma (No. 62) | orthorhombic | 0.00 | 0.3649 | -6.126 | 6.97 |
| Pm-3m (No. 221) | cubic | 0.00 | 0.5224 | -5.969 | 7.94 |
| P4/nmm (No. 129) | tetragonal | 0.00 | 0.5242 | -5.967 | 7.88 |
| Cmme (No. 67) | orthorhombic | 0.00 | 0.6218 | -5.869 | 5.25 |
| No. 0 | unknown | — | — | — | 2.25 |
| No. 0 | unknown | — | — | — | 2.26 |
| No. 0 | unknown | — | — | — | 2.32 |
Applications
Where Iron selenide is used.
Frequently Asked Questions
Common questions about Iron selenide, answered from cross-validated data.
What is FeSe?
FeSe is a thermodynamically stable, metallic iron-chalcogenide compound widely studied for its superconducting properties.
What is FeSe used for?
What is the band gap of FeSe?
Is FeSe a metal, semiconductor, or insulator?
Is FeSe thermodynamically stable?
What is the crystal structure of FeSe?
What is the density of FeSe?
How many polymorphs of FeSe are known?
What elements does FeSe contain?
Where does the data for FeSe come from?
How It Compares
Within the iron-based superconductors class.
Unlike the more complex arsenide and telluride phases such as FeAs2 or FeTe2, FeSe is distinguished by its direct role as a parent compound in the study of iron-based superconducting phenomena. While many of its siblings in the iron-chalcogenide and pnictide classes are used primarily for structural studies or as precursors, FeSe is uniquely positioned as a primary subject for investigating electronic phase transitions.
Related Compounds
Other Iron-Based Superconductors in the database.
Data sources & attribution
- materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
- cod — Data from the Crystallography Open Database. Cite: Grazulis et al., Nucleic Acids Res. 40, D420 (2012).
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