Stacking order dynamics in the quasi-two-dimensional dichalcogenide 1 T-TaS2 probed with MeV ultrafast electron diffraction

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

doi:10.1063/1.4982918

Stacking order dynamics in the quasi-two-dimensional dichalcogenide 1 T-TaS₂ probed with MeV ultrafast electron diffraction

Struct Dyn. 2017 May 3;4(4):044020. doi: 10.1063/1.4982918. eCollection 2017 Jul.

Authors

L Le Guyader, T Chase, A H Reid¹, R K Li¹, D Svetin², X Shen¹, T Vecchione¹, X J Wang¹, D Mihailovic², H A Dürr¹

Affiliations

¹ SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
² Jozef Stefan Institute and CENN Nanocenter, Jamova 39, SI-1000 Ljubljana, Slovenia.

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-TaS₂ 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 0.3 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.