The lab research efforts are directed towards addressing basic scientific questions as well as developing novel techniques and instruments that aid in the experiments. In the following pages, you will find brief description of the research efforts underway in this lab along these two directions.

 Projects

Techniques

Publication

• J. Williams, F. Zhou, T. Sun, Z. Tao, K. Chang, K. Makino, M. Berz, P.M. Duxbury, and C.-Y. Ruan, Active control of bright electron beams with RF optics for femtosecond microscopy, Struc. Dyn. 4 (A tribute to Ahmed Zewail), 044035 (2017).
• F. Zhou, J. Williams, C.-Y. Ruan, Femtosecond electron spectroscopy in an electron microscope with high-brightness beams, Chem. Phys. Lett. 683 (Ahmed Zewail Commemoration Issue), 488 (2017).
• C.-Y. Ruan, (Perspective) Molecular imaging at 1-femtosecond resolution, Science 354, 283-284 (2016).
• Z. Tao, F. Zhou, T.–R. T. Han, D. Torres, T. Wang, N. Sepulveda, K. Chang, M. Young R. R. Lunt, C.-Y. Ruan, The nature of photoinduced phase transition and metastable states in vanadium dioxide, Scientific Reports 6, 38514 (2016).
• T-R.T. Han, F. Zhou, C.D. Malliakas, P.M. Duxbury, S.D. Mahanti, M.G. Kanatzidis, and C-Y. Ruan, Exploration of metastability and hidden phases in correlated electron crystals visualized by femtosecond optical doping and electron crystallography. Science Advances 1, e1400173 (2015).
• H. Zhang, J. Portman, Z. Tao, P.M. Duxbury, C.-Y. Ruan, K. Makino, and M. Berz, The Differential Algebra Based Multiple Level Fast Multipole Algorithm for 3D Space Charge Field Calculation and Photoemission Simulation, Micros. Microana., 21 (S4), 224 (2015).
• J. Portman, H. Zhang, K. Makino, C.-Y. Ruan, M. Berz, P. M. Duxbury, Multiscale Modeling of the Ultrafast electron microscope: From the photocathode to the sample,Adv. Imag. Elect. Phys., 191, 117 (2015).
• H. Zhang, Z. Tao, C.-Y. Ruan, M. Berz, Differential algebra based multiple level fast multipole algorithm, Adv. Imag. Elect. Phys., 191, 56 (2015).
• C.-Y. Ruan, P. M. Duxbury, M. Berz, , Z. Liu, I. C. Khoo, Eds., The perspectives of femtosecond imaging and spectroscopy of complex materials using electrons. Ultrafast Nonlinear Imaging and Spectroscopy II, Proc. of SPIE, vol. 9198 (2014).
• K. Chang, R.A. Murdick, T.-R.T. Han, F. Yuan, and C.-Y. Ruan, Light-induced charge carrier dynamics at nanostructured interfaces investigated by ultrafast electron diffractive photovoltammetry. Book chapter in Quantum Dot Solar Cells, Springer Series in Materials Science, 2014.
• J. Portman, H. Zhang, Z. Tao, K. Makino, M. Berz, P.M. Duxbury, and C.-Y. Ruan, Computational and experimental characterizations of high-brightness beams for femtosecond electron imaging and spectroscopy. Appl. Phys.  Lett. 103, 253115 (2013).
• Z. Tao, T.-R. T. Han, C.-Y. Ruan, Anisotropic electron-phonon coupling investigated by ultrafast electron crystallography: Three-temperature model. Phys. Rev. B 87, 235124 (2013).
• C.-Y. Ruan, Four-dimensional electron nanocrystallography, Research in Optical Sciences:OSA Technical Digest (Optical Society of America, 2012), paper IT3D.5.
• Z. Tao, T.-R. T. Han, S. D. Mahanti, P. M. Duxbury, F. Yuan, C.-Y. Ruan, K. Wang, J. Wu, Decoupling of structural and electronic phase transitions in VO2. Phys. Rev. Lett. 109, 166406 (2012).
• T.-R. T. Han, Z. Tao, S.D. Mahanti, K. Chang, C.-Y.  Ruan, C. D. Malliakas, M. G. Kanatzidis, Structural dynamics of two-dimensional charge-density waves in CeTe3 investigated by ultrafast electron crystallography. Phys. Rev. B 86, 075145 (2012).
• Z. Tao, H. Zhang, P.M. Duxbury, M. Berz, C.-Y. Ruan, Space charge effects in ultrafast electron diffraction and imaging. J. Appl. Phys. 111, 044316 (2012).
• K. Chang, R.A. Murdick, Z. Tao, T.-R. T. Han, C.-Y. Ruan, A brief Review: Ultrafast Electron Diffractive Voltammetry:. General Formalism and Applications. Modern Phys. Lett. B 25, 2099 (2011).
• C.L. Farrow, C-Y. Ruan, S.J.L. Billinge, Quantitative nanoparticle structures from electron crystallography data. Phys. Rev. B 81, 134104 (2010).
• R. K. Raman, R. A. Murdick, R. J. Worhatch, Y. Murooka, S. D. Mahanti, T-R. T. Han, and C-Y. Ruan, Electronically driven fragmentation of Ag nanocrystals revealed by ultrafast electron crystallography. Phys. Rev. Lett. 104, 123401(2010).
• R.K. Raman, Z. Tao, T-R. Han, C-Y. Ruan, Ultrafast imaging of photoelectron packets generated from graphite surface. Appl. Phys. Lett. 95, 181108(2009).
• C-Y. Ruan, Y. Murooka, R.K. Raman, R.A. Murdick, R. J. Worhatch, A. Pell, The development and applications of ultrafast electron nanocrystallography (Review article). Micros. Microanal. special issue on Ultrafast electron microscopy and ultrafast sciences, 15, 323 (2009).
• R.K. Raman, Y. Murooka, C-Y. Ruan, T. Yang, S. Berber, D. Tomanek, Direct observation of optically induced transient structures in graphite using ultrafast electron crystallography. Phys. Rev. Lett. 101, 077401 (2008).
• R.A. Murdick, R.K. Raman, Y. Murooka, C.-Y. Ruan, Photovoltage dynamics of the hydroxylated Si(111) surface investigated by ultrafast electron diffraction. Phys. Rev. B 77, 245329(2008).
• C.-Y. Ruan, Y. Murooka, R.K. Raman, R.A. Murdick, Dynamics of size-selected gold nanoparticles studied by ultrafast electron nanocrystallography. Nano Lett. 7, 1290 (2007).

For nonspecialists

Building a better semiconductor | PHYS.ORG

Ultrafast electron microscope development | LSJ

At MSU, it's goodbye NY minute, hello femtosecond | WKAR

Diamonds aren't forever | Physical Review Focus