Pressure-induced high-Tc superconducting phase in FeSe: Correlation between anion height and Tc
Pressure-induced high-Tc superconducting phase in FeSe: Correlation between anion height and Tc
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DOI：
10.1103/physrevb.81.205119
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发表时间：
2010-05-15
影响因子：
3.7
通讯作者：
Akimitsu, J.
中科院分区：
文献类型：
--
作者：
Okabe, H.;Takeshita, N.;Akimitsu, J.
在本研究中，我们在 1-16.0 GPa 的压力范围和 4-300 K 的温度下对多晶 FeSe 进行了高压电阻率测量。从零电阻率温度对 T-c 进行精确评估表明，T-c 显示出略微扭曲的圆顶形曲线，在 6 GPa 时具有最大 T-c（偏移）（30 K）。随着压力的施加，高于 T-c 的电阻率的温度依赖性急剧变化为线性依赖性，即在 3 GPa 以上出现高 T-c 相。我们发现 T-c 和 Se 高度之间存在显着的相关性：Se 高度越低，T-c 增强得越多。此外，这种关系广泛适用于其他铁磷族化物，强烈表明高温超导性只能出现在最佳阴离子高度（类似于1.38埃）附近。基于这些结果，我们建议阴离子高度应被视为含有各种阴离子的铁基超导体的T-c的关键决定因素。
In this study, we performed high-pressure electrical resistivity measurements of polycrystalline FeSe in the pressure range of 1-16.0 GPa at temperatures of 4-300 K. A precise evaluation of T-c from zero-resistivity temperatures revealed that T-c shows a slightly distorted dome-shaped curve with maximum T-c(offset) (30 K) at 6 GPa. With the application of pressure, the temperature dependence of resistivity above T-c changes dramatically to a linear dependence, that the high-T-c phase appears above 3 GPa. We found a striking correlation between T-c and the Se height: the lower the Se height, the more enhanced is T-c. Moreover, this relation is broadly applicable to other iron pnictides, strongly indicating that high-temperature superconductivity can appear only around the optimum anion height (similar to 1.38 angstrom). On the basis of these results, we suggest that the anion height should be considered as a key determining factor of T-c of iron-based superconductors containing various anions.