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Updated: Nov 4, 2025
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Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals
Published on: May 29, 2018
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Geometric Photon-Drag Effect and Nonlinear Shift Current in Centrosymmetric Crystals.
Li-Kun Shi1,2, Dong Zhang3,4,5, Kai Chang3,4,5
1Division of Physics and Applied Physics, Nanyang Technological University, Singapore 637371, Republic of Singapore.
Physical Review Letters
|May 28, 2021
Summary
A novel photon-drag effect activates nonlinear shift currents in centrosymmetric crystals. This discovery enables new photocurrent probes for studying material interband coherences, previously inaccessible in these materials.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Optoelectronics
Background:
- Nonlinear shift currents (bulk photovoltaic currents) are typically absent in crystals with inversion symmetry.
- Understanding interband transitions in centrosymmetric materials is crucial for advanced electronic and photonic applications.
Purpose of the Study:
- To demonstrate that a nonzero shift current can be activated in centrosymmetric crystals.
- To introduce the photon-drag effect as a mechanism for generating shift currents.
- To establish a new method for probing material properties.
Main Methods:
- Theoretical analysis of photon-drag effect in centrosymmetric crystals.
- Investigation of the geometric origin of the shift current dipole.
- Exploring enhancement mechanisms through polariton coupling.
Main Results:
- A nonzero shift current can be generated in centrosymmetric crystals via the photon-drag effect.
- This photon-drag shift current exhibits a purely transverse response, stemming from its geometric origin.
- Coupling to polaritons significantly enhances the photon-drag shift current.
Conclusions:
- The photon-drag effect provides a new pathway to generate and detect nonlinear optical responses in centrosymmetric materials.
- This approach offers a sensitive tool to study interband coherences in materials previously inaccessible to photocurrent probes.
- The findings open new avenues for exploring and utilizing optical properties of a wide range of materials.
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