Systematic study of the spin and orbital ordering for the wide class of distorted perovskite oxides based on realistic modeling

在第一性原理电子结构计算的基础上，建立了具有扭曲钙钛矿结构的RMO_3系列化合物（R为三价元素，M为Ti、V、Mn）的微观低能模型。利用该模型系统地分析了晶格畸变和电子相关对RMO_3磁性结构的影响。详细讨论了RMnO_3中形成复杂磁性结构的微观相互作用，这种微观相互作用打破了反转对称，引起了铁电活性。用贝里相形式计算了电子极化，补充了分析。

On the basis of first-principles electronic structure calculations, the microscopic low-energy models were constructed for the series of RMO_3 compounds (where R is the trivalent element and M is Ti, V, or Mn) with distorted perovskite structure. The model was used for systematic analysis of the effect of lattice distortions and electron correlations on the magnetic structure of RMO_3. The microscopic interactions responsible for the formation of complex magnetic structures in manganites RMnO_3, which breaks the inversion symmetry and give rise to the ferroelectric activity, are discussed in details. The analysis is supplemented by calculations of electronic polarization using the Berry-phase formalism.