Oxygen vacancy induced site-selective Mott transition in LaNiO3
Oxygen vacancy induced site-selective Mott transition in LaNiO3
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LaNiO3 中氧空位诱导的位点选择性莫特转变
DOI：
10.1103/physrevb.103.085110
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发表时间：
2021
影响因子：
3.7
通讯作者：
Park, Hyowon
中科院分区：
文献类型：
--
作者：
Liao, Xingyu;Singh, Vijay;Park, Hyowon
虽然相关材料中的氧空位等缺陷可以极大地改变其电子特性，但了解具有缺陷的材料中电子相关性的微观起源却一直难以捉摸。随着氧空位水平从化学计量增加，具有氧空位的镍酸镧表现出金属到绝缘体的转变。特别是，呈现出顺磁绝缘相，也稳定了下面的反铁磁状态。在这里，我们利用第一原理研究电子结构和能量学。我们发现，使用密度泛函理论和动态平均场理论获得的“位置选择性”顺磁莫特绝缘态 ()。当镍轨道被半填充时，镍八面体位点形成具有强相关性的莫特绝缘态，而具有顶端氧空位的镍方形平面位点成为带状绝缘体。我们的氧空位结果不能仅用刚性带移近似内 Ni 氧化态的纯粹变化来解释。我们的态密度解释了实验 X 射线吸收光谱测量到的未占据态的峰值分裂源自空位有序结构中的两个非等价 Ni 离子。
While defects such as oxygen vacancies in correlated materials can modify their electronic properties dramatically, understanding the microscopic origin of electronic correlations in materials with defects has been elusive. Lanthanum nickelate with oxygen vacancies,, exhibits the metal-to-insulator transition as the oxygen vacancy levelincreases from the stoichiometric. In particular,exhibits a paramagnetic insulating phase, also stabilizing an antiferromagnetic state below. Here, we study the electronic structure and energetics ofusing first principles. We find thatexhibits a “site-selective” paramagnetic Mott insulating state atas obtained using density functional theory plus dynamical mean field theory (). The Ni octahedron site develops a Mott insulating state with strong correlations as the Niorbital is half-filled while the Ni square-planar site with apical oxygen vacancies becomes a band insulator. Our oxygen vacancy results cannot be explained by the pure change of the Ni oxidation state alone within the rigid band-shift approximation. Ourdensity of states explains that the peak splitting of unoccupied states inmeasured by the experimental x-ray absorption spectra originates from two nonequivalent Ni ions in the vacancy-ordered structure.