Research

Being neither solid, liquid, gas, nor plasma, Warm Dense Matter (WDM) occupies a no man's land in the map of material phases. Its temperature can range from planetary cores to stellar cores (10,000 ~ 100,000 K). Not only is it prevalent throughout the universe, but it is also relevant to inertial confinement fusion (ICF) and material performance under extreme conditions. However, because of its extreme temperatures and pressures, WDM tends to be drastically transient and thus difficult to study in the laboratory. We perform a series of experiments using femtosecond lasers, XFELs, and laboratory X-ray sources to generate and probe WDM and investigate the ultrafast electronic and structural dynamics and transport properties.

Find more information from the following articles.

- J. W. Lee, M. J. Kim, et al, PRL (2021)
- B. I. Cho, et al, Sci. Rep. 6, 18843 (2016)
- B. I. Cho, et al, PRL 106, 167601 (2011)

The development of XFEL was an essential step for advancing HED science. XFEL can heat samples to a temperature of millions of degrees to produce WDM and HDM, unlike any previous device. XFEL also provides unique opportunities to study extreme materials created using other sources with various ultrafast techniques such as diffraction, scattering, imaging, and spectroscopy at short-wavelengths. The unprecedented peak brightness of XFEL also induces the nonlinear responses of matter, which were hardly observed in the short-wavelength regime. Our activities are undertaken at PAL-XFEL, European XFEL, and LCLS.

Find more information from the following articles.

- J. W. Lee, M. J. Kim, et al, PRL (2021)
- B. I. Cho, et al, PRL 119, 075002 (2017)
- B. I. Cho, et al, PRL 109, 245003 (2012)
- S. M. Vinko, et al. Nature 482, 59-62 (2012)