KAs
KAs is a thermodynamically stable, semiconducting binary compound formed from potassium and arsenic.
About KAs
KAs is a binary compound composed of potassium and arsenic that exhibits semiconducting electronic behavior. As a thermodynamically stable phase residing on the convex hull, it represents a robust structural configuration within its chemical system.
The material is characterized by a high degree of structural diversity, with numerous reported configurations across major databases. This data richness makes it a subject of interest for researchers investigating the fundamental electronic and physical properties of alkali metal pnictides.
Key Properties
Cross-validated computational properties for KAs, aggregated across 3 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 KAs. 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 KAs, 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. |
|---|---|---|---|---|---|
| — | — | 0.77 | 0.0000 | -0.463 | — |
| P212121 (No. 19) | orthorhombic | 0.76 | 0.0000 | -0.533 | — |
| P212121 (No. 19) | orthorhombic | 0.67 | 0.0000 | -3.338 | 3.01 |
| Pmma (No. 51) | orthorhombic | 0.00 | 0.1108 | -3.228 | 2.60 |
| Pmma (No. 51) | orthorhombic | 0.00 | 0.1221 | -0.411 | — |
| — | — | 0.00 | 0.1606 | -0.302 | — |
| — | — | 0.00 | 0.3597 | -0.103 | — |
| — | — | 0.00 | 0.5400 | 0.077 | — |
| — | — | 0.00 | 0.5406 | 0.078 | — |
| — | — | 0.00 | 0.5687 | 0.106 | — |
| Pbcm (No. 57) | orthorhombic | 0.00 | 0.8484 | -2.490 | 2.36 |
| — | — | 0.00 | 0.9976 | 0.535 | — |
Applications
Where KAs is used.
Frequently Asked Questions
Common questions about KAs, answered from cross-validated data.
What is KAs?
KAs is a thermodynamically stable, semiconducting binary compound formed from potassium and arsenic.
What is KAs used for?
What is the band gap of KAs?
Is KAs a metal, semiconductor, or insulator?
Is KAs thermodynamically stable?
What is the crystal structure of KAs?
How many polymorphs of KAs are known?
What elements does KAs contain?
Where does the data for KAs come from?
How It Compares
As a standalone entry in this specific chemical context, KAs serves as a primary reference point for understanding the stability and electronic behavior of potassium-arsenic systems. Its position on the convex hull establishes it as a baseline for comparing other metastable or hypothetical phases within the same elemental combination.
Data sources & attribution
- oqmd — Data from the OQMD (oqmd.org). Cite: Saal et al., JOM 65, 1501 (2013); Kirklin et al., npj Comp. Mater. 1, 15010 (2015). (CC-BY-4.0)
- jarvis — Data from JARVIS (jarvis.nist.gov), NIST. Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020). (LicenseRef-US-Gov-PD)
- materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (CC-BY-4.0)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
- cod — Data from the Crystallography Open Database (crystallography.net/cod/). Cite: Grazulis et al., J. Appl. Cryst. 42, 726 (2009). (CC0-1.0)
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