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arXiv 2106.00403cond-mat.mtrl-scicond-mat.mes-hall
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扭转MoS$_2$/WS$_2$异质双层中能带杂化与超晶格效应的可视化

Visualizing band structure hybridization and superlattice effects in twisted MoS$_2$/WS$_2$ heterobilayers

Alfred J. H. Jones, Ryan Muzzio, Sahar Pakdel, Deepnarayan Biswas, Davide Curcio, Nicola Lanatà, Philip Hofmann, Kathleen M. McCreary, Berend T. Jonker, Kenji W… 展开作者

Alfred J. H. Jones, Ryan Muzzio, Sahar Pakdel, Deepnarayan Biswas, Davide Curcio, Nicola Lanatà, Philip Hofmann, Kathleen M. McCreary, Berend T. Jonker, Kenji Watanabe, Takashi Taniguchi, Simranjeet Singh, Roland J. Koch, Chris Jozwiak, Eli Rotenberg, Aaron Bostwick, Jill A. Miwa, Jyoti Katoch, Søren Ulstrup

备注：
31 pages, 6 figures in the main text and 5 figures in the supporting information
发表信息：
2D Mater. 9 015032 (2022)
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AI总结：

本研究通过微聚焦角分辨光电子能谱直接观测了扭转MoS$_2$/WS$_2$异质双层中随扭转角变化的能带杂化与莫尔超晶格复制态，证实了莫尔势的调控作用。

摘要：

二维范德华异质结中单层过渡金属二硫属化物（TMDs）之间的原子配准失配会产生具有周期势的莫尔超晶格，该势能可通过引入材料间的扭转角进行精细调控。这种方法有望控制TMDs之间的相互作用并调控其电子能带结构，但迄今为止，尚缺乏对随扭转角变化而引入的电子结构变化的直接观测。本文研究了由单层MoS$_2$和WS$_2$组成的异质双层，其扭转角分别为$(2.0 \u00b1 0.5)^{\u00b0}$、$(13.0 \u00b1 0.5)^{\u00b0}$和$(20.0 \u00b1 0.5)^{\u00b0}$，并利用微聚焦角分辨光电子能谱研究了它们电子能带结构的差异。我们发现MoS$_2$和WS$_2$电子态在布里渊区$\bar{\mathrm{\u0393}}$点处发生强烈的层间杂化，导致从单层的直接带隙转变为异质结构中的间接带隙。在依赖于扭转角的莫尔迷你布里渊区中心，观察到杂化态的复制品。通过将实验观测与超晶格色散的密度泛函理论计算进行比较，我们确认这些复制特征源于固有的莫尔势。对这些特征的直接可视化凸显了利用扭转异质双层半导体来工程化混合电子态和超晶格以改变二维异质结构电子和光学性质的潜力。

英文摘要：

A mismatch of atomic registries between single-layer transition metal dichalcogenides (TMDs) in a two dimensional van der Waals heterostructure produces a moiré superlattice with a periodic potential, which can be fine-tuned by introducing a twist angle between the materials. This approach is promising both for controlling the interactions between the TMDs and for engineering their electronic band structures, yet direct observation of the changes to the electronic structure introduced with varying twist angle has so far been missing. Here, we probe heterobilayers comprised of single-layer MoS$_2$ and WS$_2$ with twist angles of $(2.0 \pm 0.5)^{\circ}$, $(13.0 \pm 0.5)^{\circ}$, and $(20.0 \pm 0.5)^{\circ}$ and investigate the differences in their electronic band structure using micro-focused angle-resolved photoemission spectroscopy. We find strong interlayer hybridization between MoS$_2$ and WS$_2$ electronic states at the $\bar{\mathrmΓ}$-point of the Brillouin zone, leading to a transition from a direct bandgap in the single-layer to an indirect gap in the heterostructure. Replicas of the hybridized states are observed at the centre of twist angle-dependent moiré mini Brillouin zones. We confirm that these replica features arise from the inherent moiré potential by comparing our experimental observations with density functional theory calculations of the superlattice dispersion. Our direct visualization of these features underscores the potential of using twisted heterobilayer semiconductors to engineer hybrid electronic states and superlattices that alter the electronic and optical properties of 2D 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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