Iron(II) selenide refers to a number of inorganic compounds of ferrous iron and selenide (Se2−). The phase diagram of the system Fe–Se[1] reveals the existence of several non-stoichiometric phases between ~49 at. % Se and ~53 at. % Fe, and temperatures up to ~450 °C. The low temperature stable phases are the tetragonal PbO-structure (P4/nmm) β-Fe1−xSe and α-Fe7Se8. The high temperature phase is the hexagonal, NiAs structure (P63/mmc) δ-Fe1−xSe. Iron(II) selenide occurs naturally as the NiAs-structure mineral achavalite.
| Names | |
|---|---|
| IUPAC name
Iron(II) selenide
| |
| Identifiers | |
3D model (JSmol)
|
|
| ECHA InfoCard | 100.013.798 |
| EC Number |
|
PubChem CID
|
|
| UNII | |
CompTox Dashboard (EPA)
|
|
| |
| |
| Properties | |
| FeSe | |
| Molar mass | 134.807 g/mol |
| Appearance | black crystals |
| Density | 4.72 g/cm3 |
| Melting point | 965 °C (1,769 °F; 1,238 K) |
| 0.975 mg/100mL[citation needed] | |
| Structure | |
| hexagonal / tetragonal | |
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards
|
toxic |
| Related compounds | |
Other anions
|
Iron(II) oxide Iron(II) sulfide Iron(II) telluride |
Other cations
|
Manganese(II) selenide Cobalt(II) selenide |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
| |
More selenium rich iron selenide phases are the γ phases (γ and γˈ), assigned the Fe3Se4 stoichiometry, and FeSe2, which occurs as the marcasite-structure natural mineral ferroselite, or the rare pyrite-structure mineral dzharkenite.
It is used in electrical semiconductors.[citation needed]
Superconductivity edit
β-FeSe is the simplest iron-based superconductor but with diverse properties.[2] It starts to superconduct at 8 K at normal pressure[3] but its critical temperature (Tc) is dramatically increased to 38 K under pressure,[4] by means of intercalation,[2] or after quenching at high pressures.[5] The combination of both intercalation and pressure results in re-emerging superconductivity at 48 K.[2]
In 2013 it was reported that a single atomic layer of FeSe epitaxially grown on SrTiO3 is superconductive with a then-record transition temperature for iron-based superconductors of 70 K.[6] This discovery has attracted significant attention and in 2014 a superconducting transition temperature of over 100K was reported for this system.[7]
References edit
- ^ Okamoto H (1991). "The Fe–Se (Iron-Selenium) System". Journal of Phase Equilibria. 12 (3): 383–389. doi:10.1007/BF02649932. S2CID 99966041.
- ^ a b c Yu. V. Pustovit; A. A. Kordyuk (2016). "Metamorphoses of electronic structure of FeSe-based superconductors (Review article)". Low Temp. Phys. 42 (11): 995. arXiv:1608.07751. Bibcode:2016LTP....42..995P. doi:10.1063/1.4969896. S2CID 119184569.
- ^ F.-C. Hsu; et al. (2008). "Superconductivity in the PbO-type structure α-FeSe". Proc. Natl. Acad. Sci. USA. 105 (38): 14262–14264. arXiv:0807.2369. Bibcode:2008PNAS..10514262H. doi:10.1073/pnas.0807325105. PMC 2531064. PMID 18776050.
- ^ Medvedev, S.; McQueen, T. M.; Troyan, I. A.; Palasyuk, T.; Eremets, M. I.; Cava, R. J.; Naghavi, S.; Casper, F.; Ksenofontov, V.; Wortmann, G.; Felser, C. (2009). "Electronic and Magnetic Phase Diagram of β-Fe1.01Se with superconductivity at 36.7 K under pressure". Nature Materials. 8 (8): 630–633. arXiv:0903.2143. Bibcode:2009NatMa...8..630M. doi:10.1038/nmat2491. PMID 19525948. S2CID 117714394.
- ^ Deng, Liangzi; Bontke, Trevor; Dahal, Rabin; Xie, Yu; Gao, Bin; Li, Xue; Yin, Ketao; Gooch, Melissa; Rolston, Donald; Chen, Tong; Wu, Zheng; Ma, Yanming; Dai, Pengcheng; Chu, Ching-Wu (13 July 2021). "Pressure-induced high-temperature superconductivity retained without pressure in FeSe single crystals". Proceedings of the National Academy of Sciences. 118 (28): e2108938118. arXiv:2104.05662. Bibcode:2021PNAS..11808938D. doi:10.1073/pnas.2108938118. PMC 8285973. PMID 34234019.
- ^ R. Peng; et al. (2014). "Enhanced superconductivity and evidence for novel pairing in single-layer FeSe on SrTiO3 thin film under large tensile strain". Physical Review Letters. 112 (10): 107001. arXiv:1310.3060. Bibcode:2014PhRvL.112j7001P. doi:10.1103/PhysRevLett.112.107001. PMID 24679321. S2CID 118446521.
- ^ J.-F. Ge; et al. (2014). "Superconductivity in single-layer films of FeSe with a transition temperature above 100 K". Nature Materials. 14 (3): 285–9. arXiv:1406.3435. Bibcode:2015NatMa..14..285G. doi:10.1038/nmat4153. PMID 25419814. S2CID 119227626.