Angle-dispersive x-ray powder diffraction experiments have been performed on yttrium metal up to 183 GPa. We find that the recently discovered $oF16$ structure observed in the high-$Z$ trivalent lanthanides is also adopted by yttrium above 106 GPa, pressures where it has a superconducting temperature of $\sim 20$ K. We have also refined both tetragonal and rhombohedral structures against the diffraction data from the preceding “distorted-fcc” phase and we are unable to state categorically which of these is the true structure of this phase. Finally, analysis of yttrium's equation of state reveals a marked change in the compressibility upon adoption of the $oF16$ structure, after which the compression is that of a “regular” metal. Electronic structure calculations of $oF16$-Y confirm its stability over $oF8$ structure seen in Nd and Sm, and provide insight into the nature of the shift of orbital character from $s$ to $d$ under compression.

中文翻译：

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钇中高达183 GPa的结构相变

已经对高达183 GPa的钇金属进行了角分散X射线粉末衍射实验。我们发现最近发现的$ØF16$ 在高处观察到的结构$ž$ 钇在106 GPa以上时也采用三价镧系元素，其超导温度为 $〜20$ K.我们还根据前一个“畸变fcc”相的衍射数据对了四面体和菱面体结构进行了细化，因此我们无法明确说明其中哪一个是该相的真实结构。最后，对钇的状态方程的分析表明，采用这种方法后，可压缩性发生了显着变化。$ØF16$压缩之后是“常规”金属的压缩。电子结构计算$ØF16$-Y确认其稳定性 $ØF8$ Nd和Sm中看到的结构，并提供了对从 $s$ 至 $d$ 在压缩下。