arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1204.0141cond-mat.str-el
收藏

沿[111]生长的(LaNiO $_3$)$_2$ /(LaAlO $_3$)$_N$异质结构的电子结构

Electronic structure of (LaNiO$_3$)$_2$/(LaAlO$_3$)$_N$ heterostructures grown along [111]

Andreas Rüegg, Chandrima Mitra, Alexander A. Demkov, Gregory A. Fiete

摘要:

采用第一性原理计算和有效多轨道晶格模型相结合的方法,研究了沿[111]方向生长的$_3$双层膜的电子结构. LDA能带结构很好地再现了紧束缚模型的Ni- $e_g$轨道上定义的屈曲蜂窝晶格。我们突出这个模型,其中包括几乎平坦的带,以及线性和二次带交叉点的特殊属性。局部相关的影响进行了讨论内的LDA $+U$计划和相互作用的多轨道晶格模型的Hartree-Fock近似。在很宽的相互作用参数范围内,我们发现,铁磁相是积极的青睐。我们讨论了额外的轨道顺序,可以稳定的自发陈绝缘体与手征边缘模式或交错的轨道相位与$\sqrt{3}\times\sqrt{3}$重建的单位细胞的可能性。通过研究相互作用的镍-氧晶格模型,我们发现这些轨道有序相的稳定性也依赖于电荷转移能的值。因此,控制电荷转移能量可能是在某些类别的氧化物异质结构中设计奇异电子相的重要一步。

英文摘要:

The electronic structure of a LaNiO$_3$ bilayer grown along the [111] direction and confined between insulating layers of LaAlO$_3$ is theoretically investigated using a combination of first principle calculations and effective multi-orbital lattice models. The LDA band structure is well reproduced by a tight-binding model for the Ni-$e_g$ orbitals defined on the buckled honeycomb lattice. We highlight peculiar properties of this model which include almost flat bands as well as linear and quadratic band crossing points. The effect of local correlations is discussed within the LDA$+U$ scheme and within the Hartree-Fock approximation for interacting multi-orbital lattice models. Over a wide range of interaction parameters we find that a ferromagnetic phase is energetically favored. We discuss the possibility of additional orbital order which could stabilize a spontaneous Chern insulator with chiral edge modes or a staggered orbital phase with a $\sqrt{3}\times\sqrt{3}$ reconstruction of the unit cell. By studying an interacting nickel-oxygen lattice model we find that the stability of these orbitally ordered phases also depends on the value of the charge-transfer energy. Controlling the charge-transfer energy might therefore be an important step towards engineering exotic electronic phases in certain classes of oxide heterostructures.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑