Journal Article 2 coherent phonons 2D materials 1 Research Support, Non-U.S. Gov't 1 X-ray switching 1 hierarchical structures 1 optical pump X-ray probe 1 plus ... pulse shortening 1 superatomic semiconductors 1 thin film 1 time-resolved 1 ultrafast X-ray diffraction 1 ultrafast spectroscopy 1 moins ...