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Updated: Aug 13, 2026
09:06
Piezoreflectance Spectroscopy of Optical Transitions in van der Waals Layered Crystals
Published on: May 22, 2026
Strain Engineering of Second-Harmonic Generation and Symmetry Breaking in Few-Layer ε-InSe
Danliang Zhang1, Sihan Liu1, Peiran Li1
1Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education, Hunan Research Center of the Basic Discipline for Quantum Effects and Quantum Technologies, School of Physics and Electronics, Hunan Normal University, Changsha 410081, China.
Nanomaterials (Basel, Switzerland)
|August 12, 2026
Summary
Strain engineering dynamically controls nonlinear optical properties in epsilon-phase indium selenide (ε-InSe). Applying tensile strain modulates second-harmonic generation intensity and breaks crystal symmetry, enabling tunable nonlinear optoelectronics.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Optoelectronics
Background:
- Epsilon-phase indium selenide (ε-InSe) is a non-centrosymmetric van der Waals semiconductor with inherent broken inversion symmetry.
- This unique property results in exceptional second-order nonlinear optical responses, making it promising for nonlinear optoelectronic devices.
Purpose of the Study:
- To systematically investigate the modulation of second-harmonic generation (SHG) intensity and crystal symmetry in few-layer ε-InSe using strain engineering.
- To explore the quantitative manipulation of nonlinear efficiency in ε-InSe for potential engineering applications.
Main Methods:
- Utilized a home-built straining apparatus to apply controlled uniaxial tensile strain to few-layer ε-InSe.
- Measured strain-dependent SHG intensity and angle-resolved SHG patterns to analyze the material's response.
Main Results:
- Observed a non-monotonic strain dependence of SHG intensity in few-layer ε-InSe, initially increasing and then decreasing with applied tensile strain.
- Demonstrated strain-induced modulation of lattice symmetry, evidenced by the breaking of the sixfold symmetry in the SHG patterns.
Conclusions:
- Strain engineering offers a viable route to dynamically control and tune the nonlinear optical properties of ε-InSe.
- This work paves the way for the development of flexible and tunable nonlinear optoelectronic devices based on ε-InSe.
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