论文标题
重稀土氢化物中的高TC超导性：Fermi表面上F状态的存在，嵌套与TC的值之间的相关性
High Tc superconductivity in heavy Rare Earth Hydrides: correlation between the presence of the f states on the Fermi surface, nesting and the value of Tc
论文作者
论文摘要
在压缩下包含氢框架结构的灯笼氢化物，显示出高度观察到的临界温度的超导状态。但是，到目前为止，这种现象仅在很高的压力下才观察到。在这里，我们在计算上搜索具有很高临界温度的超导体，但压力下的压力要低得多。我们发现了两个这样的Sodalite型杂质氢化物，YBH6和LUH6（YBH6的P = 70 GPa的Tc = 145 K，尤其是LUH6的Tc = 273 K p = 100 GPA）。这些引人注目的特性是Fermi表面，结构稳定性和TC值的F状态之间强烈相互关系的结果。 For example, TmH6, with unfilled 4f orbitals, is stable at 50 GPa, while it has a relatively low value of Tc of 25 K. As for the YbH6 and LuH6 compounds, they have filled f-shells and the decrease of the f-energy below the Fermi level leads to formation of the nesting regions on the Fermi surface and, as a result, to phonon "softening" and an increase in Tc.
Lanthanum hydrides, containing hydrogen framework structures under compression, display a superconducting state with a high observed critical temperature. However, this phenomenon has so far only been observed at very high pressures. Here, we computationally search for superconductors with very high critical temperatures, but at much lower pressures. We uncover two such sodalite-type clathrate hydrides, YbH6 and LuH6 (Tc =145 K at P=70 GPa for YbH6 and, especially, Tc =273 K at P=100 GPa for LuH6). These striking properties are a consequence of the strong interrelationship between the f states present at the Fermi surface, structural stability and Tc value. For example, TmH6, with unfilled 4f orbitals, is stable at 50 GPa, while it has a relatively low value of Tc of 25 K. As for the YbH6 and LuH6 compounds, they have filled f-shells and the decrease of the f-energy below the Fermi level leads to formation of the nesting regions on the Fermi surface and, as a result, to phonon "softening" and an increase in Tc.
