Electronic Properties of Some Novel Mott Insulators

两类新型Mott绝缘体的电子结构将 在材料合成和加工倡议下进行研究 冠醚醚化合物与层状过渡金属 氧化物 虽然这些氧化物被认为是传统的莫特 哈伯德模型解释的绝缘体，实际上是基态 该模型与实验布拉格中子严重不符 散射 这个模型的假设将被检验， 目标是找到一个适当的替代者， 描述观察到的自旋密度以及激发态。 冠醚衍生物的一个新特征是阴离子 仅仅是局域化的电子本身。 的计算 孤立的冠醚分子表明， 电子将追踪其谱系到高度扩散的类里德伯态 轨道被未成对电子占据。扩散特性 这些分子的电子可以使它们成为本地化， 在分子离子之间形成的空腔。 这 命题，以及有序的空间分布 磁矩在过渡金属氧化物，将探讨 使用从头算Hartree-Fock理论以及多带Hubbard 模型使用变分和扰动方法。 %%% 理论研究将作为材料的一部分进行 合成和加工倡议。 主要重点将放在 一种新的非线性材料的理论解释 冠醚 这些材料已经合成， 密歇根州和一个坚定的理论解释是必需的。 在 此外，还将对相关材料进行研究， 过渡金属氧化物，其作为前体是重要的 高温超导体的材料。

Electronic structure of two classes of novel Mott insulators will be studied under this Materials Synthesis and Processing Initiative grant: the crown-ether electrides and the layered transition metal oxides. Although these oxides are believed to be traditional Mott insulators explained by the Hubbard model, in fact the ground state of that model disagrees seriously with experimental Bragg neutron scattering. The assumptions of this model will be examined with the objective of finding an appropriate replacement that will describe the observed spin density as well as the excited states. A novel feature of the crown-ether electrides is that the anions are simply the localized electrons themselves. Calculations on isolated crown-ether molecules suggests that the localized electrons will trace their lineage to a highly diffuse Rydberg-like orbital occupied by the unpaired electron. The diffuse character of these molecular electrons may permit them to become localized in the cavities formed "between" the molecular ions. This proposition, as well as the spatial distribution of the ordered magnetic moment in the transition metal oxides, will be explored using ab initio Hartree-Fock theory as well as multi-band Hubbard models using both variational and perturbation methods. %%% Theoretical research will be conducted as part of the Materials Synthesis and Processing Initiative. The primary focus will be on a theoretical explanation of a new class of electride materials - the crown-ethers. These materials have been synthesized at Michigan State and a firm theoretical explanation is required. In addition, research will be conducted on a related material, the transition metal oxides, which is important as the precursor material for high temperature superconductors.