Department of Physics, Columbia University, New York, New York 10027, USA.
Phys Rev Lett. 2011 Nov 11;107(20):206804. doi: 10.1103/PhysRevLett.107.206804. Epub 2011 Nov 7.
Dynamical mean-field methods are used to calculate the phase diagram, many-body density of states, relative orbital occupancy, and Fermi-surface shape for a realistic model of LaNiO(3)-based superlattices. The model is derived from density-functional band calculations and includes oxygen orbitals. The combination of the on-site Hunds interaction and charge transfer between the transition metal and the oxygen orbitals is found to reduce the orbital polarization far below the levels predicted either by band-structure calculations or by many-body analyses of Hubbard-type models which do not explicitly include the oxygen orbitals. The findings indicate that heterostructuring is unlikely to produce one band-model physics and demonstrate the fundamental inadequacy of modeling the physics of late transition-metal oxides with Hubbard-like models.
动态平均场方法被用于计算基于 LaNiO(3) 的超晶格的真实模型的相图、多体态密度、相对轨道占据和费米面形状。该模型是从密度泛函能带计算中推导出来的，并包括氧轨道。发现局域 Hund 相互作用与过渡金属和氧轨道之间的电荷转移相结合，使轨道极化大大低于仅通过能带结构计算或不明确包含氧轨道的 Hubbard 型模型的多体分析所预测的水平。这些发现表明，异质结构不太可能产生单带模型物理，并证明了使用类似于 Hubbard 的模型来模拟后期过渡金属氧化物的物理是基本不充分的。
