Tantalum(IV) sulfide

Tantalum(IV) sulfide

Crystal structure showing two stacked S-Ta-S sheets
Names
Other names
tantalum disulfide
Identifiers
3D model (JSmol)
ECHA InfoCard 100.032.047 Edit this at Wikidata
  • InChI=1S/2S.Ta
  • S=[Ta]=S
Properties
TaS2
Molar mass 245.078 g/mol[1]
Appearance golden or black crystals, depending on polytype[1]
Density 6.86 g/cm3[1]
Melting point >3000 °C[1]
Insoluble[1]
Related compounds
Other anions
 Tantalum telluride
Tantalum diselenide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Tantalum(IV) sulfide is an inorganic compound with the formula TaS2. It is a layered compound with three-coordinate sulfide centres and trigonal prismatic or octahedral metal centres.[2] It is structurally similar to molybdenum disulfide MoS2, and numerous other transition metal dichalcogenides. Tantalum disulfide has three polymorphs 1T-TaS2, 2H-TaS2, and 3R-TaS2, representing trigonal, hexagonal, and rhombohedral respectively.

The properties of the 1T-TaS2 polytype have been described.[3][4][5]

CDW, the periodic distortion induced by the electron-phonon interaction,[6] is manifested by formation of a superlattice constituted by clusters of 13 atoms, which is called the Star of David (SOD), where the surrounding 12 Ta atoms move slightly towards the centre of the star.[7] there are three 1T-TaS2 charge density wave phases: commensurate charge density wave (CCDW), nearly commensurate charge density wave (NCCDW), and incommensurate charge density wave (ICCDW). In the CCDW phase, the entire material is covered with the superlattice, but in the ICCDW phase, the atoms do not move. NCCDW is the phase between the two as the SOD clusters are confined within the nearly hexagonal-shaped areas. The phase transition of 1T-TaS2 could be achieved via temperature difference, as it is one of the most investigated methods to achieve phase transition of the material. In common with many other transition metal dichalcogenide (TMD) compounds, which are metallic at high temperatures, it exhibits a series of charge-density-wave (CDW) phase transitions from 550 K to 50 K. It is unusual amongst them in showing a low-temperature insulating state below 200 K, which is believed to arise from electron correlations, similar to many oxides. The insulating state is commonly attributed to a Mott state.[8] When cooling down to 550K, 1T-TaS2 transitions from metallic to ICCDW, then the material achieves NCCDW when cooling below 350K, and finally entering CCDW below 180K. However, if the temperature change is achieved by raising the temperature, another phase could appear between the CCDW phase and the NCCDW phase. The Triclinic Charge Density Wave (TCDW) is again the hybrid state between CCDW and ICCDW, the difference is that instead of forming an enclosed hexagon area, the material forms strips with different atom shifts. When 1T-TaS2 is heated at a lower temperature, the first transition is from CCDW to TCDW at 220K; Then, continue heating the material above 280K the phase of the material transits to NCCDW.[9][10] It is also superconducting under pressure or upon doping, with a familiar dome-like phase diagram as a function of dopant, or substituted isovalent element concentration.

Metastability. 1T-TaS2 is unique, not only amongst TMDs but also amongst 'quantum materials' in general, in showing a metastable metallic state at low temperatures.[11] Switching from the insulating to the metallic state can be achieved either optically or by the application of electrical pulses. The metallic state is persistentbelow ~20K, but its lifetime can be tuned by changing the temperature. The metastable state lifetime can also be tuned by strain. The electrically-induced switching between states is of current interest, because it can be used for ultrafast energy-efficient memory devices.[12]

Because of the frustrated triangular arrangement of localized electrons, the material is suspected of supporting some form of quantum spin liquid state. It has been the subject of numerous studies as a host for intercalation of electron donors.[13]

  1. ^ a b c d e Haynes, William M., ed. (2011). CRC Handbook of Chemistry and Physics (92nd ed.). Boca Raton, FL: CRC Press. p. 4.93. ISBN 1-4398-5511-0.
  2. ^ Cite error: The named reference wilson was invoked but never defined (see the help page).
  3. ^ Williams, P. M.; Parry, G. S.; Scrub, C. B. (1974). "Diffraction evidence for the Kohn anomaly in 1T TaS2". Philosophical Magazine. 29 (3): 695–699. Bibcode:1974PMag...29..695W. doi:10.1080/14786437408213248. ISSN 0031-8086.
  4. ^ Grant, A J; Griffiths, T M; Yoffe, A D; Pitt, G D (1974-07-21). "Pressure-induced semimetal-metal and metal-metal transitions in 1T and 2H TaS2". Journal of Physics C: Solid State Physics. 7 (14): L249–L253. Bibcode:1974JPhC....7L.249G. doi:10.1088/0022-3719/7/14/001. ISSN 0022-3719.
  5. ^ Duffey, J.R.; Kirby, R.D.; Coleman, R.V. (1976). "Raman scattering from 1T-TaS2". Solid State Communications. 20 (6): 617–621. doi:10.1016/0038-1098(76)91073-5. ISSN 0038-1098.
  6. ^ Rossnagel, K (2011-05-11). "On the origin of charge-density waves in select layered transition-metal dichalcogenides". Journal of Physics: Condensed Matter. 23 (21): 213001. Bibcode:2011JPCM...23u3001R. doi:10.1088/0953-8984/23/21/213001. ISSN 0953-8984. PMID 21558606. S2CID 11260341.
  7. ^ Shao, D. F.; Xiao, R. C.; Lu, W. J.; Lv, H. Y.; Li, J. Y.; Zhu, X. B.; Sun, Y. P. (2016-09-14). "Manipulating charge density waves in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>1</mml:mn><mml:mi>T</mml:mi><mml:mtext>−</mml:mtext><mml:msub><mml:mi>TaS</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>by charge-carrier doping: A first-principles investigation". Physical Review B. 94 (12): 125126. arXiv:1512.06553. doi:10.1103/physrevb.94.125126. ISSN 2469-9950. S2CID 118471561.
  8. ^ Cite error: The named reference r3 was invoked but never defined (see the help page).
  9. ^ Wang, Y. D.; Yao, W. L.; Xin, Z. M.; Han, T. T.; Wang, Z. G.; Chen, L.; Cai, C.; Li, Yuan; Zhang, Y. (2020-08-24). "Band insulator to Mott insulator transition in 1T-TaS2". Nature Communications. 11 (1): 4215. doi:10.1038/s41467-020-18040-4. ISSN 2041-1723. PMC 7445232. PMID 32839433.
  10. ^ Burk, B.; Thomson, R. E.; Clarke, John; Zettl, A. (1992-07-17). "Surface and Bulk Charge Density Wave Structure in 1 T-TaS2". Science. 257 (5068): 362–364. Bibcode:1992Sci...257..362B. doi:10.1126/science.257.5068.362. ISSN 0036-8075. PMID 17832831. S2CID 8530734.
  11. ^ Cite error: The named reference Stojchevska was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Mraz was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference donor was invoked but never defined (see the help page).