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Large In-Plane Anisotropic Terahertz Emission Induced by Asymmetric Polarization in Low-Symmetric PdSe2

Authors :
Yuanyuan Huang
He Wang
Zhen Lei
Yiwen E
Jiawei Chang
Xinlong Xu
Yixuan Zhou
Wanyi Du
Source :
ACS Applied Materials & Interfaces. 13:54543-54550
Publication Year :
2021
Publisher :
American Chemical Society (ACS), 2021.

Abstract

Palladium diselenide (PdSe2) exhibits air stability, low symmetry, and high carrier mobility, resulting in unique in-plane anisotropy for polarized optoelectronic devices. However, the relationship of the symmetry and the terahertz (THz) radiation remains elusive yet significant for both the THz source in technology and nonlinear optical physics in science. Herein, we observed large in-plane anisotropic THz radiation from multilayer PdSe2 under femtosecond laser excitation. The THz emission demonstrates 2α dependence on the optical polarization angle from the resonant optical rectification combined with a background from the photocarrier acceleration under the surface depletion field. Interestingly, the in-plane THz emission along and perpendicular to the puckered direction demonstrates large anisotropy. Furthermore, the THz time-domain signals exhibit reversed polarities along the positive and negative puckered directions. This asymmetric polarization could relate to the bonding of Pd-Se, resulting in the unidirectional photon-induced current. Our results bridge the gap between the low-symmetry two-dimensional materials and the THz technology, which could promote the development of THz-polarized devices based on low-symmetry layered materials.

Details

ISSN :
19448252 and 19448244
Volume :
13
Database :
OpenAIRE
Journal :
ACS Applied Materials & Interfaces
Accession number :
edsair.doi...........604d2a427a6a04215e97ed2c0d1f44b5
Full Text :
https://doi.org/10.1021/acsami.1c16197