New materials synthesized at terapascal pressures for the first time
L. Dubrovinsky, S. Khandarkhaeva, T. Fedotenko, et al.
Materials synthesis at terapascal static pressures
Nature, 605, 274-278 (2022), https://www.nature.com/articles/s41586-022-04550-2
The state of matter changes with pressure and temperature, which allows tuning material properties. These possibilities allow to address various scientific questions related to the fundamental understanding of the universe or they may lead to the targeted design of advanced materials. Solving and refining the crystal structures of solids synthesized directly from elements in laser-heated conventional diamond anvil cells at pressures as high as up to about two megabar (200 GPa) became possible due to the synergy of expertise both in generating multi-megabar pressures and in single-crystal X-ray diffraction at ultra-high pressures, which were pioneered by Bayreuth scientists a few years ago. As the high-pressure high-temperature synthesis has become a well-established technique for materials discovery, extending such investigations to the TPa regime has been desired for a long time.
A new publication in Nature reports the methodology for experiments involving static compression to the terapascal regime with laser heating. The method was used to synthesize a novel rhenium nitride, Re7N3, and a rhenium-nitrogen alloy between ca. 600 and 900 GPa in a laser-heated double-stage diamond anvil cell. Theoretical analysis showed that the extreme compression is decisive for the stabilization of Re7N3 and other novel compounds. Full chemical and structural characterization of the materials, realized using synchrotron single-crystal X-ray diffraction on microcrystals in situ, demonstrates the capabilities of the methodology to extend high-pressure crystallography to the terapascal regime.
Crystal structures of phases observed in laser-heated double-stage diamond anvil cell. (a) Hexagonal rhenium at 905(5) GPa; (b) cubic (B1 NaCl-type) rhenium-nitrogen solid solution ReN0.2 at 730(4) GPa; (c) hexagonal Re7N3 at ~900 GPa. In Re7N3 structural units are NRe6 prisms with the nitrogen atom in the center. Rhenium atoms are grey and nitrogen atoms are blue.