LiNiO2 (LNO)基态的晶体结构和电子结构长期以来存在着实验与理论计算不一致的争议. 实验上观测到LNO是空间群为 $$R\overline3m$$ 的半导体并且有局部的Jahn-Teller (JT)畸变, 但理论计算却表明它是处于亚稳态的金属并且没有任何的JT畸变. 本文基于杂化密度泛函理论HSE06, 首次模拟了与实验等同浓度(~3%)的Ni/Li反位缺陷对LNO的影响, 发现缺陷能够有效调控LNO中的JT效应. 在LNO中引入Ni/Li反位缺陷后, 其结构发生了局部的JT畸变, 并且其带隙值约为0.5 eV, 这些计算结果都和实验现象非常吻合. Ni/Li反位通过粒径效应和库伦作用, 既能诱发JT畸变, 又能阻碍畸变之间的协同作用, 避免相变到C2/m, 而只产生局部的JT畸变. 本文提出了一种新的策略来解释LNO基态晶体结构和电子结构长期以来的争议, 对推动富镍层状材...

We investigate the effects induced by the interplay of microscopic degrees of freedom. In many cases, one has to consider spin and orbital degeneracy to explain complex structures of magnetic and orbital order. Frequently, attention is focused on electronic correlations. We study how the interaction of electrons with lattice degrees of freedom modifies the pure electronic case. Because of orbit...

Jahn-Teller theorem, proposed in 1937, predicts a distortional instability for a molecule that has symmetry based degenerate electronic states. In 1939 Krishnan emphasized the importance of this theorem for the arrangement of water molecules around the transition metal or rare earth ions in aqueous solutions and hydrated saltes, in a short and interesting paper published in Nature by pointing o...