Tungsten(IV) telluride
 WTe2 has a layered crystal structure with two different W sites | |
| Names | |
|---|---|
| Other names
tungsten ditelluride | |
| Identifiers | |
12067-76-4  | |
| 3D model (Jmol) | Interactive image |
| ECHA InfoCard | 100.031.884 |
| EC Number | 235-086-0 |
| PubChem | 82913 |
| |
| |
| Properties | |
| WTe2 | |
| Molar mass | 439.04 g/mol |
| Appearance | gray crystals |
| Density | 9.43 g/cm3, solid |
| Melting point | 1,020 °C (1,870 °F; 1,290 K) |
| Structure | |
| orthorhombic, oP12 | |
| Pmn21, No. 31 | |
| Hazards | |
| EU classification (DSD) |
not listed |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
 verify (what is ?) | |
| Infobox references | |
Tungsten(IV) telluride (WTe2) is an inorganic semimetallic chemical compound. In October 2014, tungsten ditelluride was discovered to exhibit an extremely large magnetoresistance: 13 million percent with no known saturation point.[2] The resistance is proportional to the square of the magnetic field. This may be due to the material being the first example of a compensated semimetal, in which the number of mobile holes is the same as the number of electrons.[3] The structure of tungsten ditelluride is layered, and the substance can be exfoliated into thin sheets down to monolayers. However electrons can easily move between the layers, unlike in other two dimensional semiconductors. The fraction of charge carriers is 0.005 per formula unit (WTe2).[4]
When subjected to pressure, the magnetoresistance effect in WTe2 is reduced. At a pressure of 10.5 GPa magnetoresistance disappears. Above this same pressure of 10.5 GPa tungsten ditelluride can become a superconducter. At 13.0 GPa the transition to superconductivity happens below 6.5K.[5] WTe2 was also recently predicted to be a Weyl semimetal and, in particular, to be the first example of a "Type II" Weyl semimetal, where the Weyl nodes exist at the intersection of the electron and hole pockets.[6]
References
- ↑ Lide, David R. (1998). Handbook of Chemistry and Physics (87 ed.). Boca Raton, FL: CRC Press. pp. 4–92. ISBN 0-8493-0594-2.
- ↑ Mazhar N. Ali (2014). "Large, non-saturating magnetoresistance in WTe2". Nature. 514 (7521): 205–8. arXiv:1405.0973
. doi:10.1038/nature13763. PMID 25219849. - ↑ Pletikosic, I; Ali, M N; Fedorov, A V; Cava, R J; Valla, T (2014). "Electronic Structure Basis for the Extraordinary Magnetoresistance in WTe2". Physical Review Letters. 113 (21): 216601. arXiv:1407.3576. doi:10.1103/PhysRevLett.113.216601. PMID 25479512.
- ↑ Behnia, Kamran (22 July 2015). "Viewpoint: Electrons Travel Between Loosely Bound Layers". APS Physics. Retrieved 28 July 2015.
- ↑ Kang, Defen; Zhou, Yazhou; Yi, Wei; Yang, Chongli; Guo, Jing; Shi, Youguo; Zhang, Shan; Wang, Zhe; Zhang, Chao; et al. (23 July 2015). "Superconductivity emerging from a suppressed large magnetoresistant state in tungsten ditelluride". Nature Communications. 6: 7804. doi:10.1038/ncomms8804. PMC 4525168. PMID 26203807.
- ↑ Soluyanov, Alexey A.; Gresch, Dominik; Wang, Zhijun; Wu, Quansheng; Troyer, Matthias; Dai, Xi; Bernevig, B. Andrei (2015). "Type-II Weyl semimetals". Nature. 527 (7579): 495. arXiv:1507.01603. doi:10.1038/nature15768. PMID 26607545.