Quantum phase transition in solid hydrogen at high pressure
Quantum phase transition in solid hydrogen at high pressure
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DOI：
10.1103/physrevb.100.184112
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发表时间：
2019-11
影响因子：
3.7
通讯作者：
R. Dias;O. Noked;I. Silvera
中科院分区：
文献类型：
--
作者：
R. Dias;O. Noked;I. Silvera
大量的实验和理论研究致力于确定氢的高压相图。我们提出的证据相在一个更高的压力比第三阶段和低于最近观察到的金属氢相（495 GPa）的压力。在金刚石压砧单元中，在高于360 ± 15 GPa的静压下，通过氢样品的红外（IR）光谱确定了该相，并在三个单独的实验中观察到该相。虽然早期的研究发现了只在高温下发生的新的高压相，但这种相变发生在研究的最低温度下，即10.5 K，并且陡峭的相线表明它是量子相变。该相的特征在于两个不同的红外吸收带（2950和365 GPa）。在过渡压力以上，我们观察到随着压力的增加，样品在可见光谱中强烈变暗。观测结果与mca-12晶体结构一致。
Extensive experimental and theoretical studies have been devoted to determining the high-pressure phase diagram of hydrogen. We present evidence of a phase at a higher pressure than phase III and below the pressure of the recently observed phase of metallic hydrogen (495 GPa). This phase was determined from infrared (IR) spectroscopy of hydrogen samples at static pressures above 360 ± 15 GPa in a diamond anvil cell, and has been observed in three separate experiments. Whereas earlier studies found new high-pressure phases that only occurred at elevated temperatures, this phase transition occurs at the lowest temperatures investigated, ∼5 K, and the steep phase line indicates that it is a quantum phase transition. This phase is characterized by two distinct IR absorption bands (2950 andat 365 GPa). Above the transition pressure we observe strong darkening of the sample in the visible spectrum as pressure is increased. Observations are compatible with thecmca-12 crystal structure.