Band alignment and interlayer hybridisation in transition metal dichalcogenide/hexagonal boron nitride heterostructures
Band alignment and interlayer hybridisation in transition metal dichalcogenide/hexagonal boron nitride heterostructures
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DOI：
10.1088/2053-1583/ac973c
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发表时间：
2022-07
期刊：
影响因子：
5.5
通讯作者：
S. Magorrian;A. Graham;N. Yeung;F. Ferreira;P. Nguyen;A. Barinov;V. Fal’ko;N. Wilson;N. Hine
中科院分区：
文献类型：
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作者：
S. Magorrian;A. Graham;N. Yeung;F. Ferreira;P. Nguyen;A. Barinov;V. Fal’ko;N. Wilson;N. Hine
在范德华异质结中，层与层之间的能带相对排列以及由此产生的能带杂化是决定一系列电子性质的关键因素。这项工作考察了这些对过渡金属二卤化物(TMDs)和六方氮化硼(HBN)异质结构的影响，hBN是一种普遍存在的组合，因为hBN是一种包覆材料。通过密度泛函计算结果与实验角度分辨光电子能谱(ARPES)结果的比较，我们探讨了TMD和hBN层价态之间的杂化，结果表明，它引入了TMD和hBN带之间的避免交叉，umclapp过程在个别带上打开了‘幽灵’避免交叉。对MoSe_2/hBN异质结的密度泛函理论(DFT)和ARPES谱的比较表明，与密度泛函理论相比，MoSe_2和hBN的价带在能量上进一步分离。然后，我们证明了一种新的剪刀算符可以应用于密度泛函计算中的hBN价态，以校正带对齐，并能够与ARPES进行定量比较，解释了ARPES谱中避免交叉和其他带可见性的特征。
In van der Waals heterostructures, the relative alignment of bands between layers, and the resulting band hybridisation, are key factors in determining a range of electronic properties. This work examines these effects for heterostructures of transition metal dichalcogenides (TMDs) and hexagonal boron nitride (hBN), an ubiquitous combination given the role of hBN as an encapsulating material. By comparing results of density functional calculations with experimental angle-resolved photoemission spectroscopy (ARPES) results, we explore the hybridisation between the valence states of the TMD and hBN layers, and show that it introduces avoided crossings between the TMD and hBN bands, with umklapp processes opening ‘ghost’ avoided crossings in individual bands. Comparison between density functional theory (DFT) and ARPES spectra for the MoSe2/hBN heterostructure shows that the valence bands of MoSe2 and hBN are significantly further separated in energy in experiment as compared to DFT. We then show that a novel scissor operator can be applied to the hBN valence states in the DFT calculations, to correct the band alignment and enable quantitative comparison to ARPES, explaining avoided crossings and other features of band visibility in the ARPES spectra.