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Manipulating Charge Distribution in Moiré Superlattices by Light
Ruiping Guo1,2, Haowei Chen1,3,4, Wenhui Duan1,2,5
1Tsinghua University, State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics, Beijing, 100084, China.
Physical Review Letters
|March 13, 2026
Summary
Moiré superlattices enable spatially varying charge responses to light, unlike ordinary solids. This study reveals tunable, light-controlled charge modulation in twisted bilayer MoTe2, impacting nonlinear optics.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Nonlinear Optics
Background:
- Nonlinear optical responses in solids are typically averaged over unit cells due to small lattice constants.
- Moiré superlattices offer large length scales, enabling the study of spatial variations within a supercell.
Purpose of the Study:
- To formulate a spatially resolved theory for second-order direct current (dc) charge response in moiré superlattices.
- To investigate the impact of intrasupercell spatial variations on optical responses.
- To explore all-optical control of moiré-periodic electrostatic potentials.
Main Methods:
- Developed a spatially resolved theoretical framework for second-order dc charge response.
- Analyzed the contribution of diverging analytical response coefficients.
- Applied the theory to twisted bilayer Molybdenum Ditelluride (MoTe2).
Main Results:
- Uniform optical illumination induces static, spatially nonuniform charge redistribution within a moiré supercell.
- This effect is ubiquitous and not restricted by crystalline symmetries.
- A dominant contribution leads to linear-in-time growth of charge redistribution due to local dc photocurrents.
- Demonstrated strong, tunable charge modulation in twisted bilayer MoTe2 controlled by light intensity and frequency.
Conclusions:
- Intrasupercell degrees of freedom are crucial for understanding nonlinear optical responses in moiré superlattices.
- The findings open avenues for in situ, all-optical control of moiré-periodic electrostatic potentials.
- Highlights the potential for qualitatively richer nonlinear optical phenomena in moiré systems.
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