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Updated: Jun 3, 2025
08:04
Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
Published on: May 27, 2020
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Optical Activity of Chiral Excitons
Peter C Sercel1, Matthew P Hautzinger1,2, Ruyi Song3
1Center for Hybrid Organic-Inorganic Semiconductors for Energy, Golden, Colorado, 80401, USA.
Advanced Materials (Deerfield Beach, Fla.)
|January 9, 2025
Summary
This study introduces a new model for chiral excitons in semiconductors, linking structural asymmetry and spin to light interactions. It explains circular dichroism in chiral materials and nanocrystals.
Area of Science:
- Condensed matter physics
- Materials science
- Optics
Background:
- Chiroptical phenomena research connects structural asymmetry, spin configuration, and light/matter interactions in chiral semiconductors.
- Spin-splitting in these systems arises from broken inversion symmetry and extended electronic states, but its link to chiroptical phenomena is unclear.
Purpose of the Study:
- Develop an analytical effective mass model for chiral excitons.
- Parameterize the model using density functional theory.
- Investigate the origins of circular dichroism in chiral semiconductors and nanocrystals.
Main Methods:
- Developed an analytical effective mass model for chiral excitons.
- Parameterized the model using density functional theory (DFT).
- Studied a 2D hybrid perovskite semiconductor and 3D perovskite nanocrystals.
Main Results:
- The model accounts for parity mixing of band edge Bloch functions due to polar distortions, enabling magnetic dipole transitions.
- Circular dichroism in chiral excitons and their continuum arises from spin-splitting via coupled Rashba-like and chiral spin-texture components.
- The model successfully describes chiroptical properties in both chiral lattice-distorted systems and non-chiral nanocrystals.
Conclusions:
- Established a theoretical framework connecting spin-splitting and chiroptical phenomena in chiral semiconductors.
- Demonstrated the model's applicability to systems with and without chiral lattice distortions.
- Advanced understanding of light-matter interactions in chiral materials.
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