论文标题
CECOSI压力诱导的CE $ -4F $电子的结构相变和可能的价不稳定
Structural Phase Transition and Possible Valence Instability of Ce$-4f$ Electron Induced by Pressure in CeCoSi
论文作者
论文摘要
在压力下，在四方化合物Cecosi上对X射线粉末衍射和电阻率测量进行了测量，以阐明压力诱导的结构过渡的相边界以及4 $ f $电子状态的变化。温度压力相图已从布拉格峰的移位和电阻率中的异常中确定。关键压力，$ p _ {\ rm s} $ $ \ sim $ \ sim $ 4.9 gpa在300 k时，$ p _ {\ rm s} $ \ sim $ \ sim $ \ sim $ 3.6 gpa在10 k处。$ p _ {\ rm s} $的减小不仅归因于逐渐减小的单位单位元素的减小，但也不会造成单位单位的启动。当将边界越过高压阶段时，电阻率显示出明显的下降，以表现出金属温度依赖性。这项研究的结果强烈表明，结构相转换可以归因于CE-4F $ Electron的价不稳定。
X-ray powder diffraction and electrical resistivity measurements were performed on the tetragonal compound CeCoSi under pressure to elucidate the phase boundary of the pressure-induced structural transition and the change in the 4$f$ electronic state. The temperature-pressure phase diagram has been determined from the shift of the Bragg peaks and from the anomaly in the resistivity. The critical pressure, $P_{\rm s}$ $\sim$ 4.9 GPa at 300 K, decreases to $P_{\rm s}$ $\sim$ 3.6 GPa at 10 K. The decrease of $P_{\rm s}$ is due not only to the decrease in volume of the unit cell but also to an anisotropic shrinkage by cooling. When crossing the boundary to the high-pressure phase, the resistivity shows a significant drop to exhibit a metallic temperature dependence. The results of this study strongly suggest that the structural phase transition can be ascribed to valence instability of Ce-$4f$ electron.
