Pressure-induced bcc-rhombohedral phase transition in vanadium metal
Pressure-induced bcc-rhombohedral phase transition in vanadium metal
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DOI：
10.1103/physrevb.103.134103
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发表时间：
2021-04
影响因子：
3.7
通讯作者：
M. Stevenson;E. J. Pace;C. Storm;S. Finnegan;G. Garbarino;Craig W. Wilson;D. McGonegle;S. Macleod;M. McMahon
中科院分区：
文献类型：
--
作者：
M. Stevenson;E. J. Pace;C. Storm;S. Finnegan;G. Garbarino;Craig W. Wilson;D. McGonegle;S. Macleod;M. McMahon
据报道，钒在30-70 GPa下经历压力诱导的bcc-菱面体相变，其转变压力对样品环境的流体静力学敏感。然而，高压相的结构是菱面体的实验证据是令人惊讶的薄弱。我们重新研究了钒压力下，154 GPa使用多晶和单晶样品，和各种不同的压力传输介质（PTM）。我们发现，只有当使用单晶样品时，才能观察到菱面体高压相;无论使用什么PTM，多晶样品的高压衍射轮廓都不适合菱面体晶格。单晶样品揭示了两个菱面体相，它们之间有连续的过渡，从立方对称性的扭曲比以前计算的要小得多。
Vanadium is reported to undergo a pressure-induced bcc-rhombohedral phase transition at 30–70 GPa, with a transition pressure that is sensitive to the hydrostaticity of the sample environment. However, the experimental evidence for the structure of the high-pressure phase being rhombohedral is surprisingly weak. We have restudied vanadium under pressure to 154 GPa using both polycrystalline and single-crystal samples, and a variety of different pressure transmitting media (PTM). We find that only when using single-crystal samples does one observe a rhombohedral high-pressure phase; the high-pressure diffraction profiles from the polycrystalline samples do not fit a rhombohedral lattice, irrespective of the PTM used. The single-crystal samples reveal two rhombohedral phases, with a continuous transition between them, and distortions from cubic symmetry are much smaller than previously calculated.