Le Guyader L, Chase T, Reid A H, Li R K, Svetin D, Shen X, Vecchione T, Wang X J, Mihailovic D, Dürr H A
SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
Jozef Stefan Institute and CENN Nanocenter, Jamova 39, SI-1000 Ljubljana, Slovenia.
Struct Dyn. 2017 May 3;4(4):044020. doi: 10.1063/1.4982918. eCollection 2017 Jul.
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 1-TaS is investigated for the first time. From the intensity of the CDW satellites aligned around the commensurate = 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 = 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.
准二维材料中不同电荷密度波（CDW）态之间的转变可能还伴随着CDW层间堆叠的变化。利用兆电子伏特超快电子衍射，首次对准二维二硫属化物1-TaS的面外堆叠顺序动力学进行了研究。从围绕相称的=1/6特征堆叠顺序排列的CDW卫星的强度发现，该相以0.3皮秒的时间常数消失。同时，在同一实验中，从不相称的=1/3特征堆叠顺序排列的CDW卫星的强度确定了具有稍慢的2.0皮秒时间常数的不相称相的出现。这些结果可能与理解最近在该化合物中发现的激光诱导亚稳“隐藏”态的金属特性有关。
