Helicity-Sensitive Terahertz Detection in Monolayer 1T′-WTe2,ACS Applied Materials & Interfaces

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Helicity-Sensitive Terahertz Detection in Monolayer 1T′-WTe2
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2024-04-15 , DOI: 10.1021/acsami.3c18898
Ting Wang _{1,

2} , Xuechao Yu _{1,

2}

Affiliation

Valleytronics, identified as electronic properties of the energy band extrema in momentum space, has been intensively revived following the emergence of two-dimensional transition metal dichalcogenides (TMDCs) as their valley information can be controlled and probed through the spin angular momentum of light. Previous optical investigations of valleytronics have been limited to the visible/near-infrared spectral regime through which the carriers of most TMDCs can be excited. Monolayer 1T′-WTe₂ with broken time-reversal symmetry provides a fertile platform to study the long-wavelength photonic properties in different valleys. Here, we employed a circularly polarized terahertz (THz) laser to selectively excite the valley of monolayer 1T′-WTe₂ and demonstrate that the helicity-dependent photoresponse is generated via the photogalvanic effect (PGE). We also observed that the photocurrent is controlled by circular polarization and the external electric field. Because of the tunable Berry curvature dipole derived from the nontrivial wave functions near the inverted gap edge in monolayer WTe₂, the bandgap can be tuned efficiently. Our results provide a versatile venue for controlling, detecting, and processing valleytronics and applications in on-chip THz imaging and quantum information processing.

中文翻译：

单层 1T′-WTe2 中的螺旋敏感太赫兹检测

谷电子学被认为是动量空间中能带极值的电子特性，随着二维过渡金属二硫化物（TMDC）的出现，谷电子学得到了大力复兴，因为它们的谷信息可以通过光的自旋角动量来控制和探测。先前对谷电子学的光学研究仅限于可见/近红外光谱范围，通过该光谱范围可以激发大多数 TMDC 的载流子。具有破缺时间反转对称性的单层1T′-WTe ₂为研究不同谷中的长波长光子特性提供了良好的平台。在这里，我们采用圆偏振太赫兹（THz）激光选择性地激发单层1T'-WTe ₂的谷，并证明螺旋性依赖的光响应是通过光电池效应（PGE）产生的。我们还观察到光电流是由圆偏振和外部电场控制的。由于单层WTe ₂中倒置带隙边缘附近的非平凡波函数衍生出可调谐贝里曲率偶极子，因此可以有效地调谐带隙。我们的研究结果为控制、检测和处理谷电子学以及片上太赫兹成像和量子信息处理中的应用提供了一个多功能的场所。

更新日期：2024-04-15

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