High Pressure Structural Parameters and Equation of State of Osmium to 207 GPa
High Pressure Structural Parameters and Equation of State of Osmium to 207 GPa
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207 GPa 的高压结构参数和锇态方程
DOI：
10.1080/23311940.2017.1376899
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Rajeev, Ahuja
中科院分区：
文献类型：
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作者：
Perreault, Christopher S.;Velisavljevic, Nenad;Vohra, Yogesh K.;Rajeev, Ahuja
在高压下研究了最不可压缩过渡金属锇（Os）。由于费米表面上六边形密排相中价电子的拓扑跃迁导致了结构异常，因此对Os有很大的兴趣。我们报告了在环境温度下使用铂作为压力标准，在207gpa压力下对Os金属的结构参数和状态方程的测量。我们在一个压力间隔紧密的同步加速器源上获得了角色散x射线衍射数据，以观察高压下轴向比的不连续或异常。x射线衍射数据的Rietveld细化显示轴比（c/a）变化缓慢，在75 GPa时具有宽的最小值。我们的数据并没有像以前的研究报道的那样，在25或150 GPa的情况下，提供任何异常行为的证据。我们的实验结果与理论计算一致，理论计算不能预测极端条件下Os中的任何异常行为。我们给出了环境温度下Os至207 GPa （V/V0= 0.761）的状态方程，并将我们的结果与先前发表的数据进行了比较。
The most incompressible transition metal osmium (Os) has been studied under high pressure. There is significant interest in Os because of the structural anomalies attributed to topological transitions in the Fermi surface for valence electrons in the hexagonal close-packed phase. We report on measurements of structural parameters and equation of state on Os metal to a pressure of 207 GPa at ambient temperature using platinum as a pressure standard. We obtained angle-dispersive X-ray diffraction data at a synchrotron source with closely spaced pressure intervals to observe any discontinuities or anomalies in the axialc/aratio at high pressures. Rietveld refinements of X-ray diffraction data show a slowly varying axial ratio (c/a) with a broad minimum at 75 GPa. Our data do not provide any evidence of anomalous behavior in thec/aratio in Os at 25 or 150 GPa as have been reported in previous studies. Our experimental results are in agreement with theoretical calculations that do not predict any anomalous behavior inc/aratio in Os under extreme conditions. We present an equation of state for Os to 207 GPa (V/V0= 0.761) at ambient temperature and compare our results with the previously published data.