AI 中文总结
研究通过第一性原理多体理论对T$^\prime$-La$_2$NiO$_4$进行研究，发现其为电荷转移绝缘体，掺杂有载流子不对称性，T$^\prime$结构无化学计量比下的近邻反铁磁有序，为层状镍酸盐关联物理研究开辟新途径。
AI 中文摘要
La$_2$NiO$_4$在自然界中以Ni位点具有八面体氧配位的所谓T结构稳定存在。受铜酸盐体系中La$_2$CuO$_4$类似多晶型物的启发，本文通过第一性原理多体理论研究了具有Ni平面四方氧配位的T$^\prime$-结构中的La$_2$NiO$_4$。假设的T$^\prime$-La$_2$NiO$_4$化合物原来是一种具有约1.8 eV铜酸盐类电荷隙的明显电荷转移绝缘体。掺杂时，显示出强烈的载流子不对称性，即空穴主要进入O(2p)衍生态，而电子可能主要在有效的Ni-$d_{x^2-y^2}$态内成为巡游态。T$^\prime$结构中化学计量比下的最近邻反铁磁有序似乎不存在，这与T结构中的强反铁磁性形成鲜明对比。我们的理论研究为具有挑战性的电荷转移特征的层状镍酸盐中的关联物理开辟了新途径，有待实验探究。
英文摘要
The La$_2$NiO$_4$ compound stabilizes in nature in the so-called T structure with octahedral oxygen coordination of the Ni site. Motivated by a similarly existing polymorph for La$_2$CuO$_4$ in the cuprate system, we here study La$_2$NiO$_4$ in the T$^\prime$-structure with square-planar oxygen coordination of Ni by means of first-principles many-body theory. The hypothetical T$^\prime$-La$_2$NiO$_4$ compound turns out to be a manifest charge-transfer insulator with a cuprate-like charge gap of $\sim 1.8$ eV. Upon doping, a strong carrier asymmetry is revealed, i.e. while holes dominantly enter O$(2p)$-derived states, electrons may become itinerant majorly within effective Ni-$d_{x^2-y^2}$ states. Nearest-neighbor antiferromagnetic ordering at stoichiometry appears absent in the T$^\prime$ structure, in stark contrast to the strong antiferromagnetism in the T structure. Our theoretical study opens up new pathways for correlation physics in layered nickelates with challenging charge-transfer signatures, awaiting experimental inquiries.
Comments4 pages, 4 figures
