Department of Material Science, S. N. Bose National Centre for Basic Sciences, JD-Block, Sector III, Salt Lake, Kolkata-700098, India.
Phys Rev Lett. 2010 Jun 25;104(25):256401. doi: 10.1103/PhysRevLett.104.256401. Epub 2010 Jun 22.
Usually metallicity accompanies ferromagnetism. K2Cr8O16 is one of the less common examples of magnetic materials, exhibiting ferromagnetism in the insulating state. Analyzing the electronic and magnetic properties within first principles electronic structure calculations, we find that the doped electrons due to K induce a charge-ordered and insulating ground state and interestingly also introduce a ferromagnetic coupling between the Cr ions. The primary considerations driving the charge ordering are found to be electrostatic ones with the charge being localized on two Cr atoms that minimize the electrostatic energy. The structural distortion that accompanies the ordering gives rise to a rare example of a charge-order driven ferromagnetic insulator.
通常情况下，金属性伴随着铁磁性。K2Cr8O16 是磁性材料中比较少见的例子之一，它在绝缘状态下表现出铁磁性。通过第一性原理电子结构计算分析电子和磁性性质，我们发现 K 掺杂引起的电子诱导了电荷有序和绝缘基态，有趣的是，它还在 Cr 离子之间引入了铁磁耦合。电荷有序的主要驱动力被发现是静电的，电荷局域在两个 Cr 原子上，以最小化静电能。伴随有序的结构变形导致了一个罕见的电荷有序驱动铁磁绝缘体的例子。
