论文标题
co $^{2+} $ in La $ _2 $ _2 $ cotio $ _6 $和（lacoo $ _3 $）$ _ 1 $ _ 1 $+（latio $ _3 $）$ _ 1 $：a dft+$ u $和DMFT研究
Origin of the orbital polarization of Co$^{2+}$ in La$_2$CoTiO$_6$ and (LaCoO$_3$)$_1$+(LaTiO$_3$)$_1$ : a DFT+$U$ and DMFT study
论文作者
论文摘要
局部轨道（轨道极化）的不平等电子占用以及对称性和退化性的降低在过渡金属氧化物的性质中起着重要作用。在这里，我们系统地检查了轨道两极分化的根本起源，以典型的形式以3 $ d $ co $^{2+} $的3 $ d $歧视，在各种旋转，轨道和结构阶段中，在双perovskite la $ _2 $ _2 $ _2 $ cotio $ _6 $和（001）超级替补级别（lacoo $ _3 $）$ _ 1 $+（latio $ _3 $）$ _ 1 $系统。由于其CO阳离子的轨道极化，超晶格引起了特别的兴趣。基于第一原理计算，我们发现健壮且可观察到的轨道极化需要通过晶格结构减少对称性。局部电子相互作用的作用是极大地增强轨道极化。
The unequal electronic occupation of localized orbitals (orbital polarization), and associated lowering of symmetry and degeneracy, play an important role in the properties of transition metal oxides. Here, we examine systematically the underlying origin of orbital polarization, taking as exemplar the 3$d$ manifold of Co$^{2+}$ in a variety of spin, orbital and structural phases in the double perovskite La$_2$CoTiO$_6$ and the (001) superlattice (LaCoO$_3$)$_1$+(LaTiO$_3$)$_1$ systems. Superlattices are of specific interest due to the large experimentally observed orbital polarization of their Co cations. Based on first principles calculations, we find that robust and observable orbital polarization requires symmetry reduction through the lattice structure; the role of local electronic interactions is to greatly enhance the orbital polarization.
