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arXiv 2012.02203cond-mat.mtrl-sci
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拓扑量子化学在量子化学中的应用

Application of topological quantum chemistry in electrides

Simin Nie, Yuting Qian, Jiacheng Gao, Zhong Fang, Hongming Weng, Zhijun Wang

摘要:

近年来发展起来的拓扑量子化学(TQC)理论将动量空间中的能带表示与实空间中的轨道性质联系起来。它为拓扑材料的诊断提供了一条有效的途径,在筛选了所有已知的拓扑结构化合物后,发现了大量的拓扑材料。另一方面,它也可以有效地揭示空间轨道特征,包括平均电荷中心和位置对称性特征。利用TQC理论和第一性原理计算中计算出的不可约表示,我们证明了通过分析能带表示(BR)可以很好地识别出空位处具有过量电子作为阴离子的带隙,而这些能带表示不能表示为原子轨道诱导的能带表示(aBR)之和.实际上,浮带(由多余电子形成)属于以空位为中心的“赝轨道”诱导的BR。换句话说,这些带被证明是非常规的离子晶体,其中一组被占据的带不是aBR的总和,而是必然包含来自空位的BR。TQC理论为在离子晶体中寻找更多的候选化合物提供了一条有希望的途径。

英文摘要:

The recently developed theory of topological quantum chemistry (TQC) has built a close connection between band representations in momentum space and orbital characters in real space. It provides an effective way to diagnose topological materials, leading to the discovery of lots of topological materials after the screening of all known nonmagnetic compounds. On the other hand, it can also efficiently reveal spacial orbital characters, including average charge centers and site-symmetry characters. By using TQC theory with the computed irreducible representations in the first-principles calculations, we demonstrate that the electrides with excess electrons serving as anions at vacancies can be well identified by analyzing band representations (BRs), which cannot be expressed as a sum of atomic-orbital-induced band representations (aBRs). In fact, the floating bands (formed by the excess electrons) belong to the BRs induced from the "pseudo-orbitals" centered at vacancies. In other words, the electrides are proved to be unconventional ionic crystals, where a set of occupied bands is not a sum of aBRs but necessarily contains a BR from vacancies. The TQC theory provides a promising avenue to pursue more electride candidates in ionic crystals.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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