Effect of nickel on the high-pressure phases in FeH
Effect of nickel on the high-pressure phases in FeH
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DOI：
10.1103/physrevb.104.224106
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发表时间：
2021-12
影响因子：
3.7
通讯作者：
H. Piet;A. Chizmeshya;Bin Chen;S. Chariton;E. Greenberg;V. Prakapenka;S. Shim
中科院分区：
文献类型：
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作者：
H. Piet;A. Chizmeshya;Bin Chen;S. Chariton;E. Greenberg;V. Prakapenka;S. Shim
富氢金属合金和化合物因其在行星中具有深层储氢和高温超导性的潜力而引起了行星地球物理学和凝聚态物理学界的兴趣。我们发现少量的Ni可以改变FeH合金体系中的相行为。在相同条件下，无Ni FeH中的面心立方结构（fcc）的稳定性与双六方紧密堆积（dhcp）结构的稳定性相反，而双六方紧密堆积（dhcp）结构的稳定性达到了33gpa的液相线。在60gpa以上，Ni抑制了四方相的稳定性，但在较高温度下稳定了fcc FeH。在相同的压力范围内，我们发现在2500 K以上的温度下，不含Ni的四方立方是稳定的。因此，在行星内部，Ni会扩大FeH系统中密集密排结构的稳定场。如果Ni含量较低，那么它在富氢行星的核心中起着重要的作用。此外，我们的研究表明，二次合金成分会严重影响多氢化物的高压稳定性。
Hydrogen-rich metal alloys and compounds have drawn interest from planetary geophysics and condensed matter physics communities because of their potential for deep hydrogen storage in planets and high-temperature superconductivity. We find that a small amount of Ni can alter the phase behavior in the FeH alloy system. Ni can stabilize the double hexagonal close-packed (dhcp) structure in FeH up to the liquidus at 33 GPa, which is in contrast with the stability of the face-centered cubic (fcc) structure in Ni-free FeH at the same conditions. Above 60 GPa, Ni suppresses the stability of the tetragonalphase but stabilizes fcc FeH at higher temperatures. At the same pressure range, we find tetragonaland cubicto be stable at temperatures above 2500 K without Ni. Therefore, in planetary interiors, Ni will expand the stability field of dense close-packed structures in the FeH system. If the Ni content is low, thenandcan play an important role in the cores of hydrogen-rich planets. Also, our study demonstrates that a secondary alloying component can severely impact the high-pressure stability of polyhydrides.