송창용 교수

We report the recording and reconstruction of x-ray diffraction patterns from single, unstained viruses, for the first time. By separating the diffraction pattern of the virus particles from that of their surroundings, we performed quantitative and high-contrast imaging of a single virion. The structure of the viral capsid inside a virion was visualized. This work opens the door for quantitative x-ray imaging of a broad range of specimens from protein machineries and viruses to cellular organell

We report the first demonstration of resonant x-ray diffraction microscopy for element specific imaging of buried structures with a pixel resolution of approximately 15 nm by exploiting the abrupt change in the scattering cross section near electronic resonances. We performed nondestructive and quantitative imaging of buried Bi structures inside a Si crystal by directly phasing coherent x-ray diffraction patterns acquired below and above the Bi M5 edge. We anticipate that resonant x-ray diffract

Despite more than a century of study, the fundamental mechanisms behind solid melting remain elusive at the nanoscale. Ultrafast phenomena in materials irradiated by intense femtosecond laser pulses have revived the interest in unveiling the puzzling processes of melting transitions. However, direct experimental validation of various microscopic models is limited due to the difficulty of imaging the internal structures of materials undergoing ultrafast and irreversible transitions. Here we overc

X-ray scattering measurements on ${\mathrm{LaAgSb}}_{2}$ have revealed the onset of charge-density-wave (CDW) modulations associated with anomalies in the resistivity and magnetic susceptibility of this compound. Below the transition temperature of ${T}_{1,\mathrm{C}\mathrm{D}\mathrm{W}}=207\mathrm{K},$ a periodic charge and lattice modulation with ${\ensuremath{\tau}}_{1}\ensuremath{\sim}0.026(2\ensuremath{\pi}/a)$ develops along the a direction of the tetragonal structure $(a<c).$ Further l

We have shown that, when the linear oversampling ratio $\ensuremath{\geqslant}2$, exactly oversampled diffraction patterns can be directly obtained from measured data through deconvolution. By using computer simulations and experimental data, we have demonstrated that exact oversampling of diffraction patterns distinctively improves the quality of phase retrieval. Furthermore, phase retrieval based on the exact sampling scheme is independent of the oversampling ratio, which can significantly red

X-ray free-electron lasers (XFELs) provide intense (∼10 12 photons per pulse) coherent X-rays with ultra-short (∼10 −14 s) pulse lengths. X-rays of such an unprecedented nature have introduced new means of atomic scale structural investigations, and discoveries are still ongoing. Effective use of XFELs would be further accelerated on a highly adaptable platform where most of the new experiments can be realized. Introduced here is the multiple-application X-ray imaging chamber (MAXIC), which is a

A magnetostriction-induced structural phase transition in a single crystal of ${\mathrm{TbNi}}_{2}{\mathrm{B}}_{2}\mathrm{C}$ has been studied by high resolution x-ray diffraction. On cooling, we have observed a tetragonal-to-orthorhombic distortion below the N\'eel temperature, 14.3 K, similar to what has been seen in ${\mathrm{ErNi}}_{2}{\mathrm{B}}_{2}\mathrm{C}.$ The mismatch between the a and b lattice parameters increases continuously with decreasing temperature up to a value of $a/b\ensur

The structures as building blocks for designing functional nanomaterials have fueled the development of versatile nanoprobes to understand local structures of noncrystalline specimens. Progress in analyzing structures of individual specimens with atomic scale accuracy has been notable recently. In most cases, however, only a limited number of specimens are inspected lacking statistics to represent the systems with structural inhomogeneity. Here, by employing single-particle imaging with X-ray fr

Ultrafast light-matter interactions enable inducing exotic material phases by promoting access to kinetic processes blocked in equilibrium. Despite potential opportunities, actively using nonequilibrium kinetics for material discovery is limited by the poor understanding on intermediate states of driven systems. Here, using single-pulse time-resolved imaging with x-ray free-electron lasers, we found intermediate states of photoexcited bismuth nanoparticles that showed kinetically reversed surfac

Resonant magnetic x-ray scattering measurements have been performed on a single crystal of ${\mathrm{TbNi}}_{2}{\mathrm{B}}_{2}\mathrm{C}$ to uniquely determine the modulation wave vector in the low-temperature orthorhombic phase. Below the transition temperature of $14.4(\ifmmode\pm\else\textpm\fi{}0.1)\mathrm{K},$ two magnetic satellite peaks develop, centered on ${(h00)}_{\mathrm{orth}}$ charge reflections. Our study shows that the longitudinal modulation of the magnetic moment is along the l

Femtosecond laser pulses drive nonequilibrium phase transitions via reaction paths hidden in thermal equilibrium. This stimulates interest to understand photoinduced ultrafast melting processes, which remains incomplete due to challenges in resolving accompanied kinetics at the relevant space-time resolution. Here, by newly establishing a multiplexing femtosecond X-ray probe, we have successfully revealed ultrafast energy transfer processes in confined Au nanospheres. Real-time images of electro