arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2602.18893cond-mat.mes-hall
收藏

石墨烯在六方氮化硼带隙中的原子级基底松弛效应

Atomistic substrate relaxation effects in the band gaps of graphene on hexagonal boron nitride

University of Seoul(首尔大学);Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST(加泰罗尼亚纳米科学技术研究所)

Jiaqi An, Nicolas Leconte, Srivani Javvaji, Youngju Park, Jeil Jung

AI总结:

研究揭示了石墨烯在六方氮化硼中带隙受扭角和基底松弛影响的特性,发现主隙在特定扭角下达到最大,二次价带隙随扭角增大而减小直至消失。

摘要:

我们评估了在电中性点和二次价带隙中,石墨烯在六方氮化硼(G/h-BN)中的原子基底晶格松弛方案的影响,这取决于扭角。对于零扭角,主隙从完全放松的悬空G/h-BN双层中约30 meV降低到当远程h-BN基底层保持刚性时的约9 meV,再降至完全刚性结构中的约3 meV。在存在松弛的情况下,主隙在约0.6度处达到最大值,这与摩尔图案与石墨烯晶格矢量对齐导致的能量稳定化相吻合,而二次价带隙从约12 meV下降到零,超过约1度的扭角。在0度到30度的扭角范围内,所有滑动配置中,约1 meV的微小但有限的主隙,具有有利于碳原子上电子占据的质子符号,持续存在,并在30度到60度的扭角范围内改变符号。

英文摘要:

We assess the impact of atomistic substrate lattice relaxation schemes in the primary band gap at charge neutrality and the secondary valence band gap of graphene on hexagonal boron nitride (G/h-BN) as a function of twist angle. For zero twist angle, the primary gap decreases from $\sim 30$~meV in fully relaxed suspended G/h-BN bilayers, to $\sim 9$~meV when the remote h-BN substrate layer is kept rigid, and down to $\sim 3$~meV in completely rigid structures. In the presence of relaxations, the primary gap shows a maximum near $\sim 0.6^{\circ}$ coinciding with energetic stabilization due to alignment between the moiré pattern and the graphene lattice vectors, while the secondary valence band gap drops from $\sim 12$~meV down to zero beyond twist angles of $\sim 1^{\circ}$. A small but finite primary gap on the order of $\sim 1$~meV, with a mass sign favoring electronic occupation of carbon atop boron, persists across twist angles from $0^{\circ}$ to $30^{\circ}$ for all sliding configurations, and switches sign for twist angles between $30^{\circ}$ and $60^{\circ}$.

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。

↑