arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2007.13043cond-mat.supr-con
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镧系元素的高温超导态

High-Tc state of Lanthanum hydrides

Hao Song, Defang Duan, Tian Cui, Vladimir Kresin

摘要:

镧系元素的高临界温度相值得特别关注,因为该相显示了观察到的最高临界温度。我们专注于评估的临界温度,同位素系数,和他们的压力依赖性的相(Fm 3m相的LaH 10化合物)。通过结合两个耦合常数的方法,描述与光学和声学模式的相互作用,和两个特征频率与第一性原理计算,我们能够分析轻氢的临界温度的振幅在这个独特的化合物中的作用。具体地,在高压下估算了254 K的临界温度和0. 45的同位素系数,结果与实验数据吻合较好。当压力进一步增加时,临界温度值的特殊降低可以通过费米表面上的平坦区域的存在和双能隙结构的出现来解释,这应该是通过隧道光谱实验观察到的。

英文摘要:

The high critical temperature phase of lanthanum hydrides deserves special attention because this phase displays the highest observed critical temperature. We focus on the evaluation of the critical temperature, isotope coefficient, and their pressure dependence of this phase (Fm3m phase of the LaH10 compound). By combining the method of two coupling constants, describing the interaction with the optical and acoustic modes, and two characteristic frequencies with first-principle calculations we are able to analyze the role of the light hydrogen in the amplitude of the critical temperature in this unique compound. Specifically, the critical temperature of 254 K and the isotope coefficient of 0.45 are evaluated at high pressure, and the results are in good agreement with the experimental data. The peculiar decrease in the value of the critical temperature upon further increase in pressure is explained by the presence of a flat region on the Fermi surface and the appearance of a two-gap structure, which should be experimentally observable by tunneling spectroscopy.

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