Monteseguro V, Sans J A, Cuartero V, Cova F, Abrikosov Igor A, Olovsson W, Popescu C, Pascarelli S, Garbarino G, Jönsson H Johan M, Irifune T, Errandonea D
Departamento de Física Aplicada-ICMUV, Universitat de València, MALTA Consolider Team, Edificio de Investigación, C/Dr. Moliner 50, 46100 Burjassot, Valencia, Spain.
European Radiation Synchrotron Facility, 38043, Grenoble, Cedex 9, France.
Sci Rep. 2019 Jun 20;9(1):8940. doi: 10.1038/s41598-019-45401-x.
The 5d transition metals have attracted specific interest for high-pressure studies due to their extraordinary stability and intriguing electronic properties. In particular, iridium metal has been proposed to exhibit a recently discovered pressure-induced electronic transition, the so-called core-level crossing transition at the lowest pressure among all the 5d transition metals. Here, we report an experimental structural characterization of iridium by x-ray probes sensitive to both long- and short-range order in matter. Synchrotron-based powder x-ray diffraction results highlight a large stability range (up to 1.4 Mbar) of the low-pressure phase. The compressibility behaviour was characterized by an accurate determination of the pressure-volume equation of state, with a bulk modulus of 339(3) GPa and its derivative of 5.3(1). X-ray absorption spectroscopy, which probes the local structure and the empty density of electronic states above the Fermi level, was also utilized. The remarkable agreement observed between experimental and calculated spectra validates the reliability of theoretical predictions of the pressure dependence of the electronic structure of iridium in the studied interval of compressions.
5d过渡金属因其非凡的稳定性和引人入胜的电子特性而在高压研究中引起了特别关注。特别是，有人提出铱金属会表现出最近发现的压力诱导电子跃迁，即在所有5d过渡金属中最低压力下的所谓芯能级交叉跃迁。在此，我们报告了通过对物质的长程和短程有序都敏感的x射线探针，对铱进行的实验结构表征。基于同步加速器的粉末x射线衍射结果突出了低压相的大稳定性范围（高达1.4 Mbar）。通过精确测定压力-体积状态方程来表征压缩行为，其体积模量为339(3) GPa，其导数为5.3(1)。还利用了x射线吸收光谱，它探测局部结构和费米能级以上电子态的空态密度。在实验光谱和计算光谱之间观察到的显著一致性，验证了在所研究的压缩区间内铱电子结构压力依赖性理论预测的可靠性。
