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Ultrafast Electron Crystallography

UED | UEM | Breaking Boundaries

Introducing the fourth (temporal) dimension to electron crystallography constitutes the realm of ultrafast electron crystallography (UEC), which allows for studies of transient nonequilibrium structures with unprecedented spatiotemporal resolution. Visualization of such structures is fundamental to understanding phase transitions and dynamics of surfaces, nano-scale materials, and molecular interfaces. In the UEC apparatus the sample is mounted on a computer-controlled goniometer. With the electron gun focusing system, both the reflection and transmission diffractions can be obtained, and the patterns are recorded by an intensified CCD camera assembly capable of single electron detection. The scattering chamber is augmented with a retractable gas dosing assembly, a residual gas analyzer and a cooling system which enables temperature-dependent experiments down to 10 K.

The first UEC experiments were conducted on crystalline silicon with different adsorbates: hydrogen, chlorine, or molecular trifluoroiodomethane, aligned by the surface. Subsequently, different crystalline or amorphous systems were studied, including those of water on hydrophilic and hydrophobic surfaces. For all of these studies (see abstracts below), clear knowledge of the dynamics of the underlying crystalline substrate is prerequisite to the investigation of interfacial phenomena in different systems. More recently, UEC was extended to study correlated systems exhibiting superconductivity, phase transitions, and ablations. Because UEC is capable of deciphering the nature of atomic motions associated with complex condensed-matter phenomena, this research is continuing on other novel materials and interfaces.

Selected Publications

Diffraction of quantum dots reveals nanoscale ultrafast energy localization, G. M. Vanacore, J. Hu, W. Liang, S. Bietti, S. Sanguinetti, A. H. Zewail, Nano Lett. 2014, 14, 6148-6154.
[Web link] [Abstract] [Top of page]



Observing (non)linear lattice dynamics in graphite by ultrafast Kikuchi diffraction, W. Liang, G. M. Vanacore, A. H. Zewail, Proc. Natl. Acad. Sci. USA 2014, 111, 5491-5496.
[Web link] [Abstract] [Top of page]



Ultrafast electron crystallography of heterogeneous structures: Gold-graphene bilayer and ligand-encapsulated nanogold on graphene, W. Liang, S. Schäfer, A. H. Zewail, Chem. Phys. Lett. 2012, 542, 8-12.
[Web link] [Abstract] [Top of page]



Ultrafast electron crystallography of monolayer adsorbates on clean surfaces: Structural dynamics, W. Liang, S. Schäfer, A. H. Zewail, Chem. Phys. Lett. 2012, 542, 1-7.
[Web link] [Abstract] [Top of page]



Structural dynamics of surfaces by ultrafast electron crystallography: Experimental and multiple scattering theory, S. Schäfer, W. Liang, A. H. Zewail, J. Chem. Phys. 2011, 135, 214201.
[Web link] [Abstract] [Top of page]



Structural dynamics of nanoscale gold by ultrafast electron crystallography, S. Schäfer, W. Liang, A. H. Zewail, Chem. Phys. Lett. 2011, 515, 278-282.
[Web link] [Abstract] [Top of page]



Primary structural dynamics in graphite, S. Schäfer, W. Liang, A. H. Zewail, New J. Phys. 2011, 13, 063030.
[Web link] [Abstract] [Top of page]



Structural dynamics and transient electric-field effects in ultrafast electron diffraction from surfaces, S. Schäfer, W. Liang, A. H. Zewail, Chem. Phys. Lett. 2010, 493, 11-18.
[Web link] [Abstract] [Top of page]



4D electron diffraction reveals correlated unidirectional behavior in zinc oxide nanowires, D.-S. Yang, C. Lao, A. H. Zewail, Science 2008, 321, 1660-1664.
[Web link] [Abstract] [Top of page]



Structural preablation dynamics of graphite observed by ultrafast electron crystallography, F. Carbone, P. Baum, P. Rudolf, A. H. Zewail, Phys. Rev. Lett. 2008, 100, 035501.
[Web link] [Abstract] [Top of page]



4D visualization of transitional structures in phase transformations by electron diffraction, P. Baum, D.-S. Yang, A. H. Zewail, Science 2007, 318, 788-792.
[Web link] [Abstract] [Top of page]



Nonequilibrium phase transitions in cuprates observed by ultrafast electron crystallography, N. Gedik, D.-S. Yang, G. Logvenov, I. Bozovic, A. H. Zewail, Science 2007, 316, 425-429.
[Web link] [Abstract] [Top of page]



Ultrafast electron crystallography. 1. Nonequilibrium dynamics of nanometer-scale structures, D.-S. Yang, N. Gedik, A. H. Zewail, J. Phys. Chem. C 2007, 111, 4889-4919.
[Web link] [Abstract] [Top of page]



Ultrafast electron crystallography. 2. Surface adsorbates of crystalline fatty acids and phospholipids, M. T. Seidel, S. Chen, A. H. Zewail, J. Phys. Chem. C 2007, 111, 4920-4938.
[Web link] [Abstract] [Top of page]



Ultrafast electron crystallography of interfacial water, C.-Y. Ruan, V. A. Lobastov, F. Vigliotti, S. Chen, A. H. Zewail, Science 2004, 304, 80-84.
[Web link] [Abstract] [Top of page]



Ultrafast electron crystallography: Transient structures of molecules, surfaces and phase transitions, C.-Y. Ruan, F. Vigliotti, V. A. Lobastov, S. Chen, A. H. Zewail, Proc. Natl. Acad. Sci. USA 2004, 101, 1123-1128.
[Web link] [Abstract] [Top of page]