Electronic structure of dense solid oxygen from insulator to metal investigated with X-ray Raman scattering
Electronic structure of dense solid oxygen from insulator to metal investigated with X-ray Raman scattering
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用 X 射线拉曼散射研究从绝缘体到金属的致密固体氧的电子结构
DOI：
10.1073/pnas.1905771116
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Irifune Tetsuo
中科院分区：
文献类型：
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作者：
Fukui Hiroshi;Anh Le The;Wada Masahiro;Hiraoka Nozomu;Iitaka Toshiaki;Hirao Naohisa;Akahama Yuichi;Irifune Tetsuo
采用密度泛函半局域广义梯度近似和非局域范德华密度泛函的从头算方法，用氧K边X射线拉曼散射光谱研究了高密度固体氧的电子结构。本文的研究表明，跃迁能(PI*、Sigma*和连续体)随着压缩的增加而增加，然后压力依赖关系的斜率在94 GPa时发生变化。斜率的变化表明电子结构在金属相变时发生了变化。PI*和Sigma*带的变化表明，致密的固体氧不仅在晶面上，而且平行于晶轴，具有金属特性。在∼为40 Gpa时，光谱的压力演化也发生变化。在计算中定性地再现了实验结果，表明致密的固体氧通过半金属转变从绝缘体转变为金属。
Electronic structures of dense solid oxygen have been investigated up to 140 GPa with oxygenK-edge X-ray Raman scattering spectroscopy with the help of ab initio calculations based on density functional theory with semilocal metageneralized gradient approximation and nonlocal van der Waals density functionals. The present study demonstrates that the transition energies (Pi*, Sigma*, and the continuum) increase with compression, and the slopes of the pressure dependences then change at 94 GPa. The change in the slopes indicates that the electronic structure changes at the metallic transition. The change in the Pi* and Sigma* bands implies metallic characteristics of dense solid oxygen not only in the crystala–bplane but also parallel to thecaxis. The pressure evolution of the spectra also changes at ∼40 GPa. The experimental results are qualitatively reproduced in the calculations, indicating that dense solid oxygen transforms from insulator to metal via the semimetallic transition.