We developed advanced synchrotron X-ray diffraction techniques (Soller slit and nano-probe for monochromatic beam rotational data collection), combined with improved sample preparation techniques (X-ray transparent gasket), towards measuring the crystal structure of hydrogen at near 2.5 mega-bar pressures.

We overcame the technical barrier of measuring XRD of hydrogen above 200 GPa, and doubled the pressure record of XRD measurement of hydrogen at room temperature.

We demonstrated that XRD of hydrogen, once considered almost impossible at ultrahigh pressure, is feasible with the correct methodology, which provide the basic and important information to understand phase transitions in solid hydrogen.

We developed advanced synchrotron nano-probe based single crystal X-ray diffraction technique tailored for measuring the crystal structure of hydrogen at ultrahigh pressures.

We solved for the first time the complex crystal structure beyond hcp of high pressure phase of solid hydrogen.

We provide a reliable method for investigating crystal structures of other high pressure phases of solid hydrogen, including metallic hydrogen.

We discovered that ‘doping’ Ar into hydrogen postpone the metallization of hydrogen by separating neighbouring hydrogen molecules.

This is the highest pressure experimental study of hydride so far (358 GPa, the pressure of earth core).

We discovered the first time an allotrope of nitrogen with black phosphorus structure, by laser heating elemental nitrogen at 150 GPa and 2200 K.

This study will promote the development of two research fields: novel two-dimensional materials with puckered layers and single-bond nitrogen extreme high-energy-density materials.

We discovered a new mechanism of phase transition between hBN to wBN by applying shear stress using rotational diamond anvil cell. The phase transition pressure is decreased to 6.7 GPa after applying shear stress, compared to 52.8 GPa under hydrostatic compression.

This study demonstrates that applying shear stress could be a new venue for synthesizing materials at lower pressure conditions.