Colossal switchable photocurrents in topological Janus transition metal dichalcogenides
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s41524-021-00499-4.pdf
Description
Published version
Size
1.72 MB
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Adobe PDF
Checksum (MD5)
671e088e9eb24e9f50d0b4efc9193de9
Author(s)
Xu, Haowei
Wang, Hua
Zhou, Jian
Guo, Yunfan
Kong, Jing
Li, Ju
Date Issued
2021
Journal
npj Computational Materials
Publisher
Springer Science and Business Media LLC
Version
Final published version
Abstract
Nonlinear optical properties, such as bulk photovoltaic effects, possess great potential in energy harvesting, photodetection, rectification, etc. To enable efficient light–current conversion, materials with strong photo-responsivity are highly desirable. In this work, we predict that monolayer Janus transition metal dichalcogenides (JTMDs) in the 1T′ phase possess colossal nonlinear photoconductivity owing to their topological band mixing, strong inversion symmetry breaking, and small electronic bandgap. 1T′ JTMDs have inverted bandgaps on the order of 10 meV and are exceptionally responsive to light in the terahertz (THz) range. By first-principles calculations, we reveal that 1T′ JTMDs possess shift current (SC) conductivity as large as 2300 nm μA V , equivalent to a photo-responsivity of 2800 mA/W. The circular current (CC) conductivity of 1T′ JTMDs is as large as ∼10 nm μA V . These remarkable photo-responsivities indicate that the 1T′ JTMDs can serve as efficient photodetectors in the THz range. We also find that external stimuli such as the in-plane strain and out-of-plane electric field can induce topological phase transitions in 1T′ JTMDs and that the SC can abruptly flip their directions. The abrupt change of the nonlinear photocurrent can be used to characterize the topological transition and has potential applications in 2D optomechanics and nonlinear optoelectronics. −2 4 −2
MIT Department
Massachusetts Institute of Technology. Department of Nuclear Science and Engineering
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
Massachusetts Institute of Technology. Department of Materials Science and Engineering
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DOI of Published Version
https://doi.org/10.1038/S41524-021-00499-4
