The study on the mechanism of ferromagnetic metal-insulator transition and novel quantum properties in chromium oxides

同步辐射X射线衍射实验的详细结构分析和电子结构计算表明，K2Cr8O16的铁磁金属-绝缘体转变是由沿c方向的四个耦合的CrO链组成的准一维柱结构中的Peierls不稳定性导致的，导致在转变温度以下形成四聚铬离子。这为完全自旋极化电子系统的Peierls转变提供了一个罕见的例子。

Detailed structure analysis by synchrotron x-ray diffraction experiments and the electronic structure calculations demonstrate that the novel ferromagnetic metal-insulator transition in K2Cr8O16 is caused by a Peierls instability in the quasi-one-dimensional column structure made of four coupled Cr-O chains running in the c direction, leading to the formation of tetramers of Cr ions below the transition temperature. This provides a rare example of the Peierls transition of fully spin-polarized electron systems.