Ca3Co2O6 中的扩展矩形成与磁有序

本文报告了针对一维磁链化合物 Ca3Co2O6 的电子结构计算结果。该计算基于密度泛函理论和局部密度近似，使用了增广球面波 (ASW) 方法。我们的结果有助于更深入地理解近期实验发现。在 particular, alternation of Co 3d low- and high-spin states along the characteristic chains is related to differences in the oxygen coordination at the inequivalent cobalt sites. Strong hybridization of the d states with the O 2p states lays ground for polarization of the latter and the formation of extended localized magnetic moments centered at the high-spin sites. In contrast, strong metal-metal overlap along the chains gives rise to intrachain ferromagnetic exchange coupling of the extended moments via the d_{3z^2-r^2} orbitals of the low-spin cobalt atoms.