Maximally localized Wannier functions in antiferromagnetic MnO within the FLAPW formalism
Maximally localized Wannier functions in antiferromagnetic MnO within the FLAPW formalism
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DOI：
10.1103/physrevb.65.184422
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发表时间：
2002-03
影响因子：
3.7
通讯作者：
M. Posternak;A. Baldereschi;S. Massidda;N. Marzari
中科院分区：
文献类型：
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作者：
M. Posternak;A. Baldereschi;S. Massidda;N. Marzari
我们计算了MnO反铁磁菱面体晶胞中的最大局域化Wannier函数。在局域自旋密度（LSD）和LSD+U方案下，用线性缀加平面波方法得到了电子Bloch函数。十三个最上面占据的自旋上带对应于纯离子方案中的Mn-1（自旋上）位点处的五个Mn 3d轨道和O-1和O-2位点处的四个O 2s/2 p轨道。最大局域化确定了每个O唯一的四个Wannier函数，它们是三角扭曲的sp（3）类轨道。它们显示出O 2s/2 p态和Mn-2的少数自旋d态之间的弱共价键，这在完全离子化的图片中是不存在的。这种键合是负责AFM排序的相互作用的指纹，其强度取决于所使用的单电子方案。这五个Mn Wannier函数都集中在Mn-1位上，并且是由晶场修改的原子轨道。它们不是由最大局域化准则唯一定义的，我们选择它们作为对角化r（2）算子的线性组合，使它们显示Mn-1位的D-3d对称性。
We have calculated the maximally localized Wannier functions of MnO in its antiferromagnetic (AFM) rhombohedral unit cell, which contains two formula units. Electron Bloch functions are obtained with the linearized-augmented-plane-wave method within both the local-spin density (LSD) and the LSD+U schemes. The thirteen uppermost occupied spin-up bands correspond in a pure ionic scheme to the five Mn 3d orbitals at the Mn-1 (spin-up) site and the four O 2s/2p orbitals at each of the O-1 and O-2 sites. Maximal localization identifies uniquely four Wannier functions for each O, which are trigonally distorted sp(3)-like orbitals. They display a weak covalent bonding between O 2s/2p states and minority-spin d states of Mn-2, which is absent in a fully ionic picture. This bonding is the fingerprint of the interaction responsible for the AFM ordering, and its strength depends on the one-electron scheme being used. The five Mn Wannier functions are centered on the Mn-1 site, and are atomic orbitals modified by the crystal field. They are not uniquely defined by the criterion of maximal localization and we choose them as the linear combinations that diagonalize the r(2) operator, so that they display the D-3d symmetry of the Mn-1 site.