Superconductivity in group Va dichalcogenides

Maaren, M.H. van; Schaeffer, G.

doi:10.1016/0031-9163(66)90902-4

Cited by 56 publications

(18 citation statements)

References 6 publications

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“…Coupled with the absence of distinctive electron-lattice coupling features (e.g, kinks near the relevant phonon energies) in ARPES, our work strongly supports a primary role for preformed excitons in the emergence of CDW order. Finally, SC at much lower T sc ≃ 200 mK has been reported in literature [28]. This can be studied using the pairing term in H res .…”

Section: Fig 3: (Color Online) Evolution Of the Spectral Function Withmentioning

confidence: 73%

Preformed Excitonic Liquid Route to a Charge Density Wave in2H−TaSe2

et al. 2011

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Recent experiments on 2H-TaSe(2) contradict the long-held view of the charge density wave arising from a nested band structure. An intrinsically strong coupling view, involving a charge density wave state arising as a Bose condensation of preformed excitons emerges as an attractive, albeit scantily investigated alternative. Using the local density approximation plus multiorbital dynamic mean field theory, we show that this scenario agrees with a variety of normal state data for 2H-TaSe(2). Based thereupon, the ordered states in a subset of dichalcogenides should be viewed as instabilities of a correlated, preformed excitonic liquid.

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Section: Fig 3: (Color Online) Evolution Of the Spectral Function Withmentioning

confidence: 73%

Preformed Excitonic Liquid Route to a Charge Density Wave in2H−TaSe2

et al. 2011

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“…[1][2][3][4][5] A number of CDW compounds are also superconducting at temperatures lower than the CDW transition temperature (T CDW ) (this is called a CDW superconductor). 1,5,6 The issue whether superconductivity and CDW states are competing or coexisting electronic states at low temperatures is a fundamental topic in condensed-matter physics. [7][8][9] Noteworthy among CDW superconductors is ZrTe 3 , which exhibits a CDW transition around 63 K and superconductivity below 2 K. This is because ZrTe 3 has characteristic features regarding its FS topology 10,11 and the nature of its superconductivity.…”

Section: Introductionmentioning

confidence: 99%

Mixed bulk-filament nature in superconductivity of the charge-density-wave conductor ZrTe3

2012

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We have shown that the superconducting transitions in ZrTe 3 are successive from filamentary to bulk, based on experimental results obtained for a superconducting specific-heat anomaly and the anisotropic superconducting transition curve of resistivity. A small jumplike superconducting specific-heat anomaly with a large and widely extended tail was observed to closely follow the anisotropic zero-resistance transition. We concluded that the jumplike anomaly signifies the onset of the long-range order of Cooper pairs with the opening of a superconducting gap at T C , while the large and widely extended tail indicates behavior induced by Cooper pairs with a very short coherence length. As a limit for a very short coherence length, we propose local pairs with Bose characteristics. As a result, we can understand that the filamentary superconductivity is caused by the local pairs, and the large and widely extended tail is in a crossover region between superconductivity induced by local pairs and that induced by Cooper pairs. Based on a discussion about the origin of the change in the pair coupling from the starting of local pairing to Cooper pairing in ZrTe 3 , we conclude that "mixed bulk-filament superconductivity" results from unique electronic structural changes in the quasi-1D + 3D (D, dimensional) Fermi surfaces after the CDW transition.

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“…21 In the NbS 2 system only the 2H-NbS 2 polytype is known to be superconducting with a critical temperature of T c ≈ 6 K, although it is worth mentioning that there are reports that found also the 3R-NbS 2 polytype to be superconducting with a very similar critical temperature. [22][23][24][25][26][27] As we shall show later in this work, these observations of superconductivity in samples of the 3R-NbS 2 polytype may likely be caused the presence of traces of 2H-NbS 2 , which are challenging to identify by means of X-ray diffraction. The challenge to prepare phase-pure samples of 2H-NbS 2 and 3R-NbS 2 has earlier been recognized by Fisher et al 28 There it was highlighted that the sulfur pressure during synthesis is crucial for the phase formation of the product.…”

Section: Introductionmentioning

confidence: 80%