Time-resolved electron diffraction employing MeV electron beams is demonstrated experimentally at the center for ultrafast diffraction and microscopy of Shanghai Jiao Tong University. A high-quality diffraction patter...Time-resolved electron diffraction employing MeV electron beams is demonstrated experimentally at the center for ultrafast diffraction and microscopy of Shanghai Jiao Tong University. A high-quality diffraction pattern is recorded by a single shot of electron pulse. Synchronization between the pump laser and the probe electron beam is achieved through measurement of electron deflection caused by the laser-induced plasmas in a metal tip. We study the ultrafast structural dynamics of the gold lattice excited by a femtosecond laser through tracing the change of Bragg peaks intensity at different time delays. It is expected that the combination of MeV ultrashort electron beams and femtoseeond laser pulses will open many new opportunities in the ultrafast and ultrasmall world.展开更多
The choice that a solid system“makes”when adopting a crystal structure(stable or metastable)is ultimately governed by the interactions between electrons forming chemical bonds.Here we analyze six prototypical binary...The choice that a solid system“makes”when adopting a crystal structure(stable or metastable)is ultimately governed by the interactions between electrons forming chemical bonds.Here we analyze six prototypical binary transition metal compounds and shed light on the connection between Mott physics and the behavior of the energy as a function of the spatial arrangement of the atoms in these systems.Remarkably,we find that the main qualitative features of this complex behavior in the Mott phase of these systems can be traced back to the fact that the strong d-electron correlations influence substantially the charge transfer mechanism,which,in turn,controls the electrostatic interactions.This result advances our understanding of the influence of strong correlations on the crystal structure,opens a new avenue for extending structure prediction methodologies to strongly correlated materials,and paves the way for predicting and studying metastability and polymorphism in these systems.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 11327902 and 11304199.
文摘Time-resolved electron diffraction employing MeV electron beams is demonstrated experimentally at the center for ultrafast diffraction and microscopy of Shanghai Jiao Tong University. A high-quality diffraction pattern is recorded by a single shot of electron pulse. Synchronization between the pump laser and the probe electron beam is achieved through measurement of electron deflection caused by the laser-induced plasmas in a metal tip. We study the ultrafast structural dynamics of the gold lattice excited by a femtosecond laser through tracing the change of Bragg peaks intensity at different time delays. It is expected that the combination of MeV ultrashort electron beams and femtoseeond laser pulses will open many new opportunities in the ultrafast and ultrasmall world.
基金N.L.,T.-H.L.and V.D.were partially supported by the NSF grant DMR-1410132the National High Magnetic Field Laboratory.N.L.was also supported by the VILLUM FONDEN via the Centre of Excellence for Dirac Materials(Grant No.11744).
文摘The choice that a solid system“makes”when adopting a crystal structure(stable or metastable)is ultimately governed by the interactions between electrons forming chemical bonds.Here we analyze six prototypical binary transition metal compounds and shed light on the connection between Mott physics and the behavior of the energy as a function of the spatial arrangement of the atoms in these systems.Remarkably,we find that the main qualitative features of this complex behavior in the Mott phase of these systems can be traced back to the fact that the strong d-electron correlations influence substantially the charge transfer mechanism,which,in turn,controls the electrostatic interactions.This result advances our understanding of the influence of strong correlations on the crystal structure,opens a new avenue for extending structure prediction methodologies to strongly correlated materials,and paves the way for predicting and studying metastability and polymorphism in these systems.
