arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2407.02785cond-mat.mtrl-sciphysics.comp-ph
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利用高通量搜索和机器学习方法识别直接带隙硅结构

Identifying Direct Bandgap Silicon Structures with High-throughput Search and Machine Learning Methods

Rui Wang, Hongyu Yu, Yang Zhong, Hongjun Xiang

AI总结:

该研究结合高通量搜索、机器学习势、ML哈密顿量与DFT计算,从2637种硅同素异形体中筛选出47种直接带隙结构,并识别22种潜在光伏材料。

摘要:

硅基发光器件的应用受到金刚石硅间接带隙性质的限制。本研究采用高通量方法来加速直接带隙硅晶体的发现。研究利用机器学习(ML)势构建了一个包含2637种硅同素异形体的数据集,随后使用ML哈密顿量模型和密度泛函理论计算进行筛选,最终识别出47种直接带隙硅结构。我们计算了这些结构的跃迁偶极矩(TDM)、能量和声子能带结构,以验证其性能。此外,我们采用HSE06泛函重新计算了这些结构的带隙。22种硅同素异形体被确定为潜在的光伏材料。其中,具有1.27 eV直接带隙的Si22-Pm,其每原子能量比金刚石硅高0.026 eV/atom。具有0.796 eV直接带隙的Si18-C2/m在所识别结构中表现出最高的TDM。具有0.907 eV直接带隙的Si16-P21/c的质量密度为2.316 g/cm3,是所识别结构中最高的,并且高于金刚石硅。具有1.69 eV直接带隙的Si12-P1结构在所识别结构中表现出最高的光谱极限最大效率(SLME),达到32.28%,超过了金刚石硅。本研究为理解硅晶体的性质提供了见解,同时提出了一种用于材料发现的系统性高通量方法。

英文摘要:

Utilizations of silicon-based luminescent devices are restricted by the indirect-gap nature of diamond silicon. In this study, the high-throughput method is employed to expedite discoveries of direct-gap silicon crystals. The machine learning (ML) potential is utilized to construct a dataset comprising 2637 silicon allotropes, which is subsequently screened using an ML Hamiltonian model and density functional theory calculations, resulting in identification of 47 direct-gap Si structures. We calculate transition dipole moments (TDM), energies, and phonon bandstructures of these structures to validate their performance. Additionally, we recalculate bandgaps of these structures employing the HSE06 functional. 22 silicon allotropes are identified as potential photovoltaic materials. Among them, the energy per atom of Si22-Pm, which has a direct bandgap of 1.27 eV, is 0.026 eV/atom higher than diamond silicon. Si18-C2/m, which has a direct bandgap of 0.796 eV, exhibits the highest TDM among identified structures. Si16-P21/c, which has a direct bandgap of 0.907 eV, has the mass density of 2.316 g/cm3, which is the highest among identified structures and higher than that of diamond silicon. The structure Si12-P1, which possesses a direct bandgap of 1.69 eV, exhibits the highest spectroscopic limited maximum efficiency (SLME) among identified structures at 32.28%, surpassing that of diamond silicon. This study offers insights into properties of silicon crystals while presenting a systematic high-throughput method for material discovery.

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