On-Chip Terahertz Spectroscopy for Dual-Gated van der Waals Heterostructures at Cryogenic Temperatures

IF 11.3 1区化学 Q1 CHEMISTRY, PHYSICAL

ACS Catalysis Pub Date : 2024-11-13 DOI:10.1021/acs.nanolett.4c04137

Junseok Seo, Zhengguang Lu, Seunghyun Park, Jixiang Yang, Fangzhou Xia, Shenyong Ye, Yuxuan Yao, Tonghang Han, Lihan Shi, Kenji Watanabe, Takashi Taniguchi, Amir Yacoby, Long Ju

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Abstract

Van der Waals heterostructures have emerged as a versatile platform to study correlated and topological electron physics. Spectroscopy experiments in the THz regime are crucial since the energy of THz photons matches that of relevant excitations and charge dynamics. However, their micrometer size and complex (dual-)gated structures have challenged such measurements. Here, we demonstrate on-chip THz spectroscopy on a dual-gated bilayer graphene device at liquid helium temperature. To avoid unwanted THz absorption by metallic gates, we developed a scheme of operation by combining semiconducting gates and optically controlled gating. This allows us to measure the clean THz response of graphene without being affected by the gates. We observed the THz signatures of electric-field-induced bandgap opening at the charge neutrality. We measured Drude conductivities at varied charge densities and extracted key parameters including effective masses and scattering rates. This work paves the way for studying novel emergent phenomena in dual-gated two-dimensional materials.

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低温条件下双门控范德瓦耳斯异质结构的片上太赫兹光谱学

范德华异质结构已成为研究相关和拓扑电子物理学的多功能平台。由于太赫兹光子的能量与相关激发和电荷动力学的能量相匹配，因此太赫兹机制下的光谱学实验至关重要。然而，太赫兹光子的微米尺寸和复杂的（双）门控结构给此类测量带来了挑战。在这里，我们展示了在液氦温度下在双栅双层石墨烯器件上进行片上太赫兹光谱分析的方法。为了避免金属栅极产生不必要的太赫兹吸收，我们开发了一种结合半导体栅极和光控栅极的操作方案。这使我们能够测量石墨烯的纯 THz 响应，而不受栅极的影响。我们观察到了电荷中性时电场诱导带隙打开的太赫兹特征。我们测量了不同电荷密度下的德鲁德电导率，并提取了包括有效质量和散射率在内的关键参数。这项工作为研究双栅二维材料中的新出现现象铺平了道路。

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来源期刊

ACS Catalysis CHEMISTRY, PHYSICAL-

CiteScore

20.80

自引率

6.20%

发文量

1253

审稿时长

1.5 months

期刊介绍： ACS Catalysis is an esteemed journal that publishes original research in the fields of heterogeneous catalysis, molecular catalysis, and biocatalysis. It offers broad coverage across diverse areas such as life sciences, organometallics and synthesis, photochemistry and electrochemistry, drug discovery and synthesis, materials science, environmental protection, polymer discovery and synthesis, and energy and fuels. The scope of the journal is to showcase innovative work in various aspects of catalysis. This includes new reactions and novel synthetic approaches utilizing known catalysts, the discovery or modification of new catalysts, elucidation of catalytic mechanisms through cutting-edge investigations, practical enhancements of existing processes, as well as conceptual advances in the field. Contributions to ACS Catalysis can encompass both experimental and theoretical research focused on catalytic molecules, macromolecules, and materials that exhibit catalytic turnover.