Giant room-temperature nonlinearities from a monolayer Janus topological semiconductor
Nonlinear optical materials possess wide applications, ranging from terahertz and mid-infrared detection to energy harvesting. Recently, the correlations between nonlinear optical responses and topological properties, such as Berry curvature and the quantum metric tensor, have stimulated great inter...
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Main Authors | , , , , , , , , , , , , , , , , , , |
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Format | Journal Article |
Language | English |
Published |
03.04.2023
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Subjects | |
Online Access | Get full text |
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Summary: | Nonlinear optical materials possess wide applications, ranging from terahertz
and mid-infrared detection to energy harvesting. Recently, the correlations
between nonlinear optical responses and topological properties, such as Berry
curvature and the quantum metric tensor, have stimulated great interest. Here,
we report giant room-temperature nonlinearities in an emergent
non-centrosymmetric two-dimensional topological material, the Janus transition
metal dichalcogenides in the 1T' phase, which are synthesized by an advanced
atomic-layer substitution method. High harmonic generation, terahertz emission
spectroscopy, and second harmonic generation measurements consistently reveal
orders-of-the-magnitude enhancement in terahertz-frequency nonlinearities of
1T' MoSSe (e.g., > 50 times higher than 2H MoS$_2$ for 18th order harmonic
generation; > 20 times higher than 2H MoS$_2$ for terahertz emission). It is
elucidated that such colossal nonlinear optical responses come from topological
band mixing and strong inversion symmetry breaking due to the Janus structure.
Our work defines general protocols for designing materials with large
nonlinearities and preludes the applications of topological materials in
optoelectronics down to the monolayer limit. This two-dimensional form of
topological materials also constitute a unique platform for examining origin of
the anomalous high-harmonic generation, with potential applications as building
blocks for scalable attosecond sources. |
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DOI: | 10.48550/arxiv.2304.00750 |