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arXiv · 1703.05035

Stacking order dynamic in the quasi-two-dimensional dichalcogenide 1T-TaS$_2$ probed with MeV ultrafast electron diffraction

L. Le Guyader·T. Chase·A. Reid·R. K. Li·D. Svetin·X. Shen·T. Vecchione·X. J. Wang·D. Mihailovic·H. A. Dürr
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Abstract

Transitions between different charge density wave (CDW) states in quasi-two-dimensional materials may be accompanied also by changes in the inter-layer stacking of the CDW. Using MeV ultrafast electron diffraction, the out-of-plane stacking order dynamics in the quasi-two-dimensional dichalcogenide 1T-TaS$_2$ is investigated for the first time. From the intensity of the CDW satellites aligned around the commensurate $l$ = 1/6 characteristic stacking order, it is found out that this phase disappears with a 0.5 ps time constant. Simultaneously, in the same experiment, the emergence of the incommensurate phase, with a slightly slower 2.0 ps time constant, is determined from the intensity of the CDW satellites aligned around the incommensurate $l$ = 1/3 characteristic stacking order. These results might be of relevance in understanding the metallic character of the laser-induced metastable "hidden" state recently discovered in this compound.

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L. Le Guyader, T. Chase, A. Reid, R. K. Li, D. Svetin, X. Shen, T. Vecchione, X. J. Wang, D. Mihailovic, H. A. Dürr. 2017-03-15. Stacking order dynamic in the quasi-two-dimensional dichalcogenide 1T-TaS$_2$ probed with MeV ultrafast electron diffraction. https://doi.org/10.1063/1.4982918

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