Faraday rotations,ellipticity,and circular dichroism in magneto-optical spectrum of moiré superlattices

• 作者: J A Crosse Pilkyung Moon
• 来源期刊: 中国物理B（英文版）
• 年，卷（期）: 2021,（7）
• 所属期刊栏目: SPECIAL TOPIC—Twistronics
• 页码范围: 21-36
• 页数: 16页
• 语种: 英文
• DOI: 10.1088/1674-1056/ac051f

摘要

We study the magneto-optical conductivity of a number of van der Waals heterostructures,namely,twisted bilayer graphene,AB-AB and AB-BA stacked twisted double bilayer graphene and monolayer graphene and AB-stacked bilayer graphene on hexagonal boron nitride.As the magnetic field increases,the absorption spectrum exhibits a self-similar recursive pattern reflecting the fractal nature of the energy spectrum.Whilst twisted bilayer graphene displays only weak circular dichroism,the other four structures display strong circular dichroism with monolayer graphene and AB-stacked bilayer graphene on hexagonal boron nitride being particularly pronounced owing to strong inversion symmetry breaking properties of the hexagonal boron nitride layer.As the left and right circularly polarized light interact with these structures differently,plane-polarized incident light undergoes a Faraday rotation and gains an ellipticity when transmitted.The size of the respective angles is on the order of a degree.