Correlation-driven charge order at the interface between a Mott and a band insulator.
Correlation-driven charge order at the interface between a Mott and a band insulator.
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DOI：
10.1103/physrevlett.99.016802
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发表时间：
2007-07
影响因子：
8.6
通讯作者：
R. Pentcheva;W. Pickett
中科院分区：
文献类型：
--
作者：
R. Pentcheva;W. Pickett
为了研究数字Mott绝缘体LaTiO_3和带绝缘体SrTiO_3的界面，我们应用局域密度近似下的关联带理论，包括Hubbard U到（n，m）多层膜，1<或=n，m<或=9，使用具有较大横向周期性的单元电池。如果在Ti上的现场排斥是足够大的模型的莫特绝缘行为的未扭曲的LaTiO 3，在界面处的电荷不平衡被发现在所有情况下，以容纳通过双折射（Ti 4 ++ Ti 3+），电荷排序，和Ti 3 + dx-轨道排序，与反铁磁交换耦合之间的自旋在界面层。晶格弛豫通过移动（轻微但重要的）较低的哈伯德带导致导电行为，但电荷和轨道顺序对弛豫是鲁棒的。
To study digital Mott insulator LaTiO3 and band insulator SrTiO3 interfaces, we apply correlated band theory within the local density approximation including a Hubbard U to (n, m) multilayers, 1<or=n, m<or=9 using unit cells with larger lateral periodicity. If the on-site repulsion on Ti is big enough to model the Mott insulating behavior of undistorted LaTiO3, the charge imbalance at the interface is found in all cases to be accommodated by disproportionation (Ti4++Ti3+), charge ordering, and Ti3+ dxy-orbital ordering, with antiferromagnetic exchange coupling between the spins in the interface layer. Lattice relaxations lead to conducting behavior by shifting (slightly but importantly) the lower Hubbard band, but the charge and orbital order is robust against relaxation.