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arXiv 2301.04750cond-mat.mtrl-sciphysics.comp-ph
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六方氮化硼/石墨烯异质结中由缺陷引起的电荷转移:一项从头算研究

Charge transfer due to defects in hexagonal boron nitride/graphene heterostructures: an ab initio study

Madhava Krishna Prasad, Oras A. Al-Ani, Jonathan P. Goss, Jonathan D. Mar

AI总结:

本研究采用DFT研究h-BN/石墨烯异质结中四类本征点缺陷与石墨烯的电荷转移,指出传统方法的电荷分配问题并提出态密度积分法,发现空位缺陷发生单电子转移且缺陷几何结构与电荷态相关,为相关器件应用及方法推广提供支撑。

摘要:

我们采用密度泛函理论(DFT),研究了六方氮化硼(h-BN)/石墨烯异质结中h-BN点缺陷与石墨烯之间的电荷转移,涵盖多种本征缺陷:氮空位、硼空位、氮反位缺陷和硼反位缺陷。研究表明,传统的通过空间区分不同原子的电荷来计算电荷转移的方法存在电荷分配不当的问题,因此我们提出了一种依赖态密度积分的替代方法。我们还发现,由于缺陷能级附近态密度的变化,电荷转移的DFT计算存在晶胞尺寸依赖性。结果表明,氮反位缺陷和硼反位缺陷不参与电荷转移,而氮空位和硼空位会发生一个完整电子的转移。此外,我们还证明缺陷几何结构的变化对应于缺陷电荷态的变化。本研究结果对于涉及h-BN/石墨烯异质结中h-BN缺陷与石墨烯之间电荷转移的各类器件应用具有重要价值,同时我们的方法可切实推广到多种点缺陷和异质结体系。

英文摘要:

Using density functional theory (DFT), we study charge transfer between hexagonal boron nitride (h-BN) point defects and graphene in h-BN/graphene heterostructures for a range of intrinsic defects -- nitrogen vacancy, boron vacancy, nitrogen antisite and boron antisite. We show that traditional methods that calculate charge transfer by spatial discrimination of charge to different atoms suffer from the misallocation of charge and introduce an alternative method that relies on the integration of the density of states. We also show that DFT calculations of charge transfer have cell size dependencies due to a change in the density of states in the vicinity of the defect levels. Our results indicate that the nitrogen and boron anitsites do not participate in charge transfer, whereas the nitrogen and boron vacancies experience the transfer of a whole electron. Additionally, we show that a change in the geometry of a defect corresponds to a change in the charge state of the defect. The results of our study will be invaluable for a wide variety of device applications that involve charge transfer between h-BN defects and graphene in h-BN/graphene heterostructures, while our methodology can be feasibly extended to a wide range of point defects and heterostructures.

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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