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arXiv 2305.03339cond-mat.mtrl-sciphysics.comp-ph
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团簇旋转诱导的单层C60丰富结构多晶型

Rich structural polymorphism of monolayer C60 from cluster rotation

Xueao Li, Fan Zhang, Xuefei Wang, Weiwei Gao, Jijun Zhao

AI总结:

本研究通过第一性原理计算发现,单层C60中团簇旋转能垒低,存在多种能量接近实验相的多晶型,且光激发、电子静电掺杂可调控准四方相稳定性,为二维团簇组装材料的相工程提供了新思路。

摘要:

近期实验成功制备出单层及少层C60聚合物,为合成二维团簇组装材料铺平了道路。与具有SO(3)对称性的原子相比,作为超原子的团簇(如C60)额外具备旋转自由度,极大丰富了超原子组装材料的相空间。通过第一性原理计算,我们发现准四方单层C60结构中团簇旋转的能垒极低,约为10 meV/原子。如此低的旋转能垒催生了一系列四方C60多晶型,其能量与实验准四方(expt-qT)相接近。类似地,我们还发现多种动力学稳定的准六方单层C60结构,其能量比实验准六方相高出不超过7 meV/原子。计算结果表明,光激发电子-空穴对以及电子静电掺杂可有效调控准四方C60多晶型的相对能量。尤其值得注意的是,原本不稳定的单层expt-qT相在进行电子静电掺杂后会变为动力学稳定态。相比之下,不同准六方多晶型之间的相对能量对电子静电掺杂不敏感。

英文摘要:

The recent experimental fabrication of monolayer and few-layer C60 polymers paves the way for synthesizing two-dimensional cluster-assembled materials. Compared to atoms with the SO(3) symmetry, clusters as superatoms (e.g., C60) have an additional rotational degree of freedom, greatly enriching the phase spaces of superatom-assembled materials. Using first-principles calculations, we find the energy barriers of cluster rotation in quasi-tetragonal monolayer C60 structures are rather low (about 10 meV/atom). The small rotational energy barriers lead to a series of tetragonal C60 polymorphs with energies that are close to the experimental quasi-tetragonal (expt-qT) phase. Similarly, several dynamically stable quasi-hexagonal monolayer C60 structures are found to have energies within 7 meV/atom above the experimental quasi-hexagonal phase. Our calculations demonstrate photo-excited electron-hole pairs and electrostatic doping of electrons can effectively modulate the relative energies of quasi-tetragonal C60 polymorphs. Particularly, the unstable monolayer expt-qT phase becomes dynamically stable when it is electrostatically doped with electrons. In contrast, the relative energies between different quasi-hexagonal polymorphs are insensitive to electrostatic doping of electrons.

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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