论文标题
石墨烯/氮化硼扭曲的Quadrilayer超级晶格中的电场可调层极化
Electric field-tunable layer polarization in graphene/boron nitride twisted quadrilayer superlattices
论文作者
论文摘要
最近观察到的在六角硼硼化硼（HBN）夹在AB双层石墨烯中的非常规的铁电性提出了一个新的平台，以操纵多层范德华异质结构中操纵相关相。我们为AB双层石墨烯提供了一个低能连续模型，该模型由HBN或石墨烯的顶层和底层包裹，具有两个独立的扭曲角。对于石墨烯/HBN异质结构，我们表明扭曲角度不对称会导致价值和导带的层极化。我们还表明，平面外的位移场不仅会调节层极化，还会使低能带变平。我们扩展了模型，以表明Quadrilayer石墨烯异质结构的电子结构由顶部和底部石墨烯层封装的AB双层石墨烯组成，可以通过外部电场来调节。
The recently observed unconventional ferroelectricity in AB bilayer graphene sandwiched by hexagonal Boron Nitride (hBN) presents a new platform to manipulate correlated phases in multilayered van der Waals heterostructures. We present a low-energy continuum model for AB bilayer graphene encapsulated by the top and bottom layers of either hBN or graphene, with two independent twist angles. For the graphene/hBN heterostructures, we show that twist angle asymmetry leads to a layer polarization of the valence and conduction bands. We also show that an out-of-plane displacement field not only tunes the layer polarization but also flattens the low-energy bands. We extend the model to show that the electronic structures of quadrilayer graphene heterostructure consisting of AB bilayer graphene encapsulated by the top and bottom graphene layers can similarly be tuned by an external electric field.
