Enhanced superconductivity in atomically thin TaS2

• Published in: Nature communications Vol. 7; no. 1; p. 11043
• Main Authors: Navarro-Moratalla, Efrén, Island, Joshua O., Mañas-Valero, Samuel, Pinilla-Cienfuegos, Elena, Castellanos-Gomez, Andres, Quereda, Jorge, Rubio-Bollinger, Gabino, Chirolli, Luca, Silva-Guillén, Jose Angel, Agraït, Nicolás, Steele, Gary A., Guinea, Francisco, van der Zant, Herre S. J., Coronado, Eugenio
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 17-03-2016; Nature Publishing Group; Nature Portfolio
• Subjects: 140/133; 639/301/119/1003; 639/301/119/544; Humanities and Social Sciences; multidisciplinary; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms11043

The ability to exfoliate layered materials down to the single layer limit has presented the opportunity to understand how a gradual reduction in dimensionality affects the properties of bulk materials. Here we use this top–down approach to address the problem of superconductivity in the two-dimensional limit. The transport properties of electronic devices based on 2H tantalum disulfide flakes of different thicknesses are presented. We observe that superconductivity persists down to the thinnest layer investigated (3.5 nm), and interestingly, we find a pronounced enhancement in the critical temperature from 0.5 to 2.2 K as the layers are thinned down. In addition, we propose a tight-binding model, which allows us to attribute this phenomenon to an enhancement of the effective electron–phonon coupling constant. This work provides evidence that reducing the dimensionality can strengthen superconductivity as opposed to the weakening effect that has been reported in other 2D materials so far.
As a material's thickness decreases towards the atomic-scale, dimensional confinement may promote behaviour not found in the bulk, with potential technological applications. Here, the authors study superconductivity in TaS
2
as it is mechanically exfoliated towards the two-dimensional limit.