Oral
Electronic structure of dense solid oxygen from insulator to metal | Authors: Hiroshi Fukui (U HYOGO - Graduate School of Material Science, University of Hyogo) ; Le Te Anh (RIKEN - Computational Engineering Applications Unit, RIKEN) ; Masahiro Wada (U HYOGO - Graduate School of Material Science, University of Hyogo) ; Nozomu Hiraoka (NSRRC - SPring-8 Taiwan Beamline Office, National Synchrotron Radiation Research Center) ; Toshiaki Iitaka (RIKEN - Computational Engineering Applications Unit, RIKEN) ; Naohisa Hirao (JASRI - Japan Synchrotron Radiation Research Institute) ; Yuichi Akahama (U HYOGO - Graduate School of Material Science, University of Hyogo) ; Tetsuo Irifune (GRC - Geodynamics Research Center, Ehime University) |
Abstract: Electronic structures of dense solid oxygen have been investigated up to 140 GPa with oxygen K-edge X-ray Raman scattering spectroscopy with the help of ab-initio calculation. The present study demonstrates that the oxygen K edge shifts to higher energy with compression, then to lower energy from 94 GPa, and to higher energy again above 115 GPa. The characteristic negative shift of the K edge has been observed in the metallic transition. The negative shifts of Pi* and Sigma* bands imply the metallic character of dense solid oxygen not only in the crystal a-b plane but also parallel to the c axis. The experimental results support the proposed crystallographic structure of C2/m for the metallic phase. The pressure evolution of the spectra was changed around 40 GPa. The experimental results were qualitatively reproduced in the calculations, indicating that dense solid oxygen transforms from insulator to metal via semimetal.Electronic structures of dense solid oxygen have been investigated up to 140 GPa with oxygen K-edge X-ray Raman scattering spectroscopy with the help of ab-initio calculation. The present study demonstrates that the oxygen K edge shifts to higher energy with compression, then to lower energy from 94 GPa, and to higher energy again above 115 GPa. The characteristic negative shift of the K edge has been observed in the metallic transition. The negative shifts of Pi* and Sigma* bands imply the metallic character of dense solid oxygen not only in the crystal a-b plane but also parallel to the c axis. The experimental results support the proposed crystallographic structure of C2/m for the metallic phase. The pressure evolution of the spectra was changed around 40 GPa. The experimental results were qualitatively reproduced in the calculations, indicating that dense solid oxygen transforms from insulator to metal via semimetal.
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