Suchergebnisse

The authors thank T. Chauveau (LSPM) for help with Rietveld analysis, A. Jamali (LRCS) for assistance with SEM measurements, and Drs. Y. Tange (SPring-8) and N. Guignot (SOLEIL) for help in synchrotron experiments that were carried out during beamtimes allocated to proposals 2017A1047 & 2018A1121 at SPring-8 and proposal 20170092 at SOLEIL. Ab initio calculations have been performed using Rurik and Arkuda supercomputers. This work was financially supported by the European Union's Horizon 2020 Research and Innovation Programme under Flintstone2020 project (grant agreement No. 689279). Z.W. thanks the National Science Foundation of China (grant No. 11604159). A.R.O. thanks the Russian Ministry of Science and Higher Education (grant 2711.2020.2 to leading scientific schools). ; New boron-rich sulfde B6S and selenide B6Se have been discovered by combination of high pressure – high temperature synthesis and ab initio evolutionary crystal structure prediction, and studied by synchrotron X-ray difraction and Raman spectroscopy at ambient conditions. As it follows from Rietveld refnement of powder X-ray difraction data, both chalcogenides have orthorhombic symmetry and belong to Pmna space group. All experimentally observed Raman bands have been attributed to the theoretically calculated phonon modes, and the mode assignment has been performed. Prediction of mechanical properties (hardness and elastic moduli) of new boron-rich chalcogenides has been made using ab initio calculations, and both compounds were found to be members of a family of hard phases. ; Horizon 2020 Framework Programme 689279 Ministry of Science and Higher Education of the Russian Federation 2711.2020.2 National Natural Science Foundation of China 11604159 Center of Excellence has received funding from the European Union's Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART²