Thickness-scaling phonon resonance: A systematic study of hexagonal boron nitride from monolayers to bulk crystals
Thickness-scaling phonon resonance: A systematic study of hexagonal boron nitride from monolayers to bulk crystals
复制标题
厚度缩放声子共振：六方氮化硼从单层到块状晶体的系统研究
DOI：
10.1063/5.0094039
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发表时间：
2022-10
影响因子：
3.2
通讯作者：
Xiaojie Jiang;Mingyuan Chen;Jiahan Li;Parvin Fathi-hafshejani;Jialiang Shen;Yiming Jin;W. Cai;M. Mahjouri‐Samani;J. Edgar;S. Dai
中科院分区：
文献类型：
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作者：
Xiaojie Jiang;Mingyuan Chen;Jiahan Li;Parvin Fathi-hafshejani;Jialiang Shen;Yiming Jin;W. Cai;M. Mahjouri‐Samani;J. Edgar;S. Dai
声子是影响材料的热、电和光学性质的重要晶格振动。在这项工作中，我们研究了红外声子共振的原型货车范德华（vdW）材料-六方氮化硼（hBN）-与厚度范围从单层到散装，特别是超薄晶体原子层小于20。我们的综合实验和建模结果表明，在hBN的层数增加的面内声子共振的强度有系统的增加，灵敏度下降到一个原子层。虽然声子共振的厚度依赖性揭示了我们的纳米镜的天线性质，声子极化激元波长的线性厚度缩放表明超薄hBN层中电磁双曲性的保留。我们的结论应该是通用的vdW材料和异质结构的组成层的数量可以方便地控制的基本共振。在我们的工作中揭示的厚度依赖的声子共振和声子极化激元也表明所需的热和纳米光子功能的VDW工程机会。
Phonons are important lattice vibrations that affect the thermal, electronic, and optical properties of materials. In this work, we studied infrared phonon resonance in a prototype van der Waals (vdW) material—hexagonal boron nitride (hBN)—with the thickness ranging from monolayers to bulk, especially on ultra-thin crystals with atomic layers smaller than 20. Our combined experimental and modeling results show a systematic increase in the intensity of in-plane phonon resonance at the increasing number of layers in hBN, with a sensitivity down to one atomic layer. While the thickness-dependence of the phonon resonance reveals the antenna nature of our nanoscope, the linear thickness-scaling of the phonon polariton wavelength indicates the preservation of electromagnetic hyperbolicity in ultra-thin hBN layers. Our conclusions should be generic for fundamental resonances in vdW materials and heterostructures where the number of constituent layers can be conveniently controlled. The thickness-dependent phonon resonance and phonon polaritons revealed in our work also suggest vdW engineering opportunities for desired thermal and nanophotonic functionalities.