Structure of 2H-TaS2

Meetsma, Auke; Wiegers, G.A.; Haange, R.J.; Boer, J. L. de

doi:10.1107/s0108270190000014

Cited by 65 publications

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“…Note that the Nb-S distances in 2H-NbS2 are not known accurately because 1 for the z coordinate of S is the deviation from not known. For Pbl/3TaS2, the Ta(1)-S distances, 2.45(2)A (3x) and 2.48(2)A (3x), and Ta(2)-S distances, 2.487(13)A (6x), are within the standard deviations equal to those (2.468(2) A) in 2H-TaS2 [4], and intercalates such as In2/3TaS2 (2.471(2)A) [24], Feu3TaS2 (2.49,~) and Mnl/3TaS2 (2.48/~) [21][22][23]. The Nb-Nb distances (3.336/~) and the Ta-Ta distances (3.325/~) are about 0.01 A larger than those in 2H-NbS2 and 2H-TaS2.…”

Section: Discussion Of the Structuresmentioning

confidence: 66%

“…both based on post-transition metal atoms present in one-third of the available trigonal-antiprismatic holes between NbS2 or TaS2 sandwiches which have Nb or Ta in trigonal-prismatic coordination by sulfur. The NbS2 and TaS2 sublattices are similar to those of the pure dichalcogenides 2H-NbS2 (a = 3.324, c = 11.95/~ [3]), and 2H-TaS2 (a= 3.314, c ----12.097 & [4]), the space group being P63/mmc). Due to the occupation by Sn and Pb of only onethird of the available sites, the a axis is v/3 times that of Nb and Ta dichalcogenides and the c axes are expanded by about 2.5 A.…”

Section: Introductionmentioning

confidence: 63%

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Crystal structure and band structure calculations of and

Fang

Wiegers

Meetsma

et al. 1996

Physica B: Condensed Matter

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Crystal structure and band structure calculations of Pb1/3TaS2 and Sn1/3NbS2 Link to publication in University of Groningen/UMCG research database Citation for published version (APA): Fang, C. M., Wiegers, G. A., Meetsma, A., de Groot, R. A., & Haas, C. (1996). Crystal structure and band structure calculations of Pb1/3TaS2 and Sn1/3NbS2. Physica B, 226(4), 259 -267. DOI: 10.1016/0921-4526(96)00271-2 Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. AbstractThe crystal structures of Pb~/3TaS2 and Sn~/3NbS2 were determined using single-crystal X-ray diffraction. The space group is P6322 and the unit cell dimensions are: a = 5.759(1 ), c = 14.813(1)A and a = 5.778(1), c = 14.394(1 )/~, for the Pb and Sn compounds, respectively. The post-transition metal atoms occupy one-third of the trigonal-antiprismatic holes between sandwiches NbS2 and TaS2. The Nb and Ta atoms are in trigonal-prismatic coordination by sulfur atoms. The stacking of sandwiches is the same as in 2H disulfides. The arrangement of the post-transition metal atoms is different for the two compounds. A bond valence calculation showed Sn and Pb to be divalent.Ab initio band structure calculations were performed for Snl/3NbS2 using the localized spherical wave method, and for Pbl/3TaS2 with the augmented spherical wave method with spin-orbital interactions included. The calculations show that the rigid band model is approximately valid for the electronic structures; the main difference with those of 2H-NbS2 and 2H-TaS2 being the presence of Sn 5s and 5p (Pb 6s and 6p) bands and a larger S 3p/Nb(Ta) 4d (5d) gap in the intercalates (l.0eV for Snl/3NbS2, 1.3 eV for Pbl/3TaS2). The Sn 5s (Pb 6s) bands are at the bottom (bonding) and top (antibonding) of the valence bands which range from about -7 to about 0 eV. The conduction bands are composed of Nb 4d:2 or Ta 5d~2 orbitals hybridized with S 3p. These bands are filled to about 0.3 holes per Nb (Ta), corresponding to a donation of two electrons per Sn (Pb). I. IntroductionDiSalvo et al. [1] were the first to study the compounds MxTaS2 with M a post-transition element (Ga, In, Ge, Sn, Pb); they used X-ray powder methods for characterization. Eppinga and Wiegers [2] synthesized, besides the compounds already found by DiSalvo et al.

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Section: Discussion Of the Structuresmentioning

confidence: 66%

Section: Introductionmentioning

confidence: 63%

Crystal structure and band structure calculations of and

Fang

Wiegers

Meetsma

et al. 1996

Physica B: Condensed Matter

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“…In the family of TMDC's, the sample T aS 2 may be one of the model systems to tackle this problem. Two basic structures of T aS 2 were found and defined by the different orientation of stacking chalcogen sheets, one is 1T − T aS 2 with T a in octahedral coordination with S atoms, another is 2H − T aS 2 with T a in trigonal-prismatic coordina-tion with S atoms 17,18 . The system 1T − T aS 2 shows four CDW phase transitions accompanied by changes in lattice parameters and resistivity when temperature decreases, the CDW formation could be explained by the Fermi surface nesting 16,17,19 .…”

Section: Introductionmentioning

confidence: 99%

Fabrication and superconductivity ofNaxTaS2crystals

et al. 2005

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In this paper we report the growth and superconductivity of N axT aS2 crystals. The structural data deduced from X-ray diffraction pattern shows that the sample has the same structure as 2H − T aS2. A series of crystals with different superconducting transition temperatures (Tc) ranging from 2.5 K to 4.4 K were obtained. It is found that the Tc rises with the increase of N a content determined by Energy-Dispersive x-ray microanalysis(EDX) of Scanning Electron Microscope (SEM) on these crystals. Compared with the resistivity curve of un-intercalated sample 2H − T aS2 (Tc = 0.8 K, TCDW ≈ 70 K), no signal of charge density wave (CDW) was observed in samples N a0.1T aS2 and N a0.05T aS2. However, in some samples with lower Tc, the CDW appears again at about 65 K. Comparison between the anisotropic resistivity indicates that the anisotropy becomes smaller in samples with more N a intercalation (albeit a weak semiconducting behavior along c-axis) and thus higher Tc. It is thus concluded that there is a competition between the superconductivity and the CDW. With the increase of sodium content, the rise of Tc in N axT aS2 is caused mainly by the suppression to the CDW in 2H − T aS2, and the conventional rigid band model for layered dichalcogenide may be inadequate to explain the changes induced by the slight intercalation of sodium in 2H − T aS2.

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“…Furthermore, the chloride hydrides of rareearth metals LnXH and LnXH x also have the same stacking sequence as hydrogen occupies the respective nitride site [87,[89][90][91]. Another related compound is TaS 2 in its 2H-structure (hexagonal, P6 3 /mmc), in which the van-derWaals gap is located between sulfide anions [92,93] [95][96][97], but those are not separated by van-der-Waals gaps. As nitride contain- …”

Section: Compounds With Structures Related To B-mnxmentioning

confidence: 99%

Superconducting nitride halides MNX (M = Ti, Zr, Hf; X = Cl, Br, I)

Schurz

Shlyk

Schleid

et al. 2011

Zeitschrift Für Kristallographie

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Abstract. Two different polymorphs of the metal nitride halides MNX (M ¼ Ti, Zr, Hf; X ¼ Cl, Br, I) are known to crystallize in layered structures. The two crystal structures differ in the way 2 1 {X[M 2 N 2 ]X} slabs are stacked along the c-axes. Metal atoms and/or organic molecules can be intercalated into the van-der-Waals gap between these layers. After such an electron-doping via intercalation the prototypic band insulators change into superconductors with moderate high critical temperatures T c up to 25.5 K. This review gathers information on synthesis routes, structural characteristics and properties of the prototypic nitride halides and the derivatives after electron-doping with a focus on superconductivity.

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Structure of 2H-TaS2

Abstract: Introduction. Several modifications [see Hulliger (1976) for a review] are known for tantalum disulfide, the forms extensively studied being 1T-TaS2, space group P3ml [Cd(OH)2-type structure], with Ta in octahedral coordination by S, and 2H-TaS2, space

Cited by 65 publications

References 10 publications

Crystal structure and band structure calculations of and

Crystal structure and band structure calculations of and

Fabrication and superconductivity ofNaxTaS2crystals

Superconducting nitride halides MNX (M = Ti, Zr, Hf; X = Cl, Br, I)

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