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Updated: Dec 8, 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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Exciton-Phonon Interaction and Relaxation Times from First Principles
Hsiao-Yi Chen1, Davide Sangalli2,3, Marco Bernardi1
1Department of Applied Physics and Materials Science, California Institute of Technology, Pasadena, California 91125, USA.
Physical Review Letters
|September 21, 2020
Summary
This study introduces a rigorous first-principles method to calculate exciton-phonon interactions and dynamics. This advances understanding of exciton scattering processes in materials.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Computational Quantum Chemistry
Background:
- Electron-phonon interactions are crucial for electron dynamics in materials.
- Quantifying exciton-phonon interactions and scattering remains a significant challenge.
- First-principles modeling offers accurate insights into material properties.
Purpose of the Study:
- To develop a rigorous first-principles approach for computing exciton-phonon (ex-ph) interactions.
- To investigate exciton dynamical processes influenced by phonons.
- To provide a general framework for studying exciton dynamics.
Main Methods:
- Derivation of ex-ph matrix elements and relaxation times from the ab initio Bethe-Salpeter equation.
- Application to bulk hexagonal boron nitride.
- Mapping of ex-ph relaxation times against exciton momentum and energy.
Main Results:
- Accurate prediction of phonon-assisted photoluminescence in hexagonal boron nitride.
- Analysis of temperature and phonon-mode dependence of ex-ph scattering.
- Detailed mapping of exciton relaxation times as a function of momentum and energy.
Conclusions:
- The developed method provides a rigorous framework for computing ex-ph interactions.
- This approach enables detailed investigation of exciton dynamics in various materials.
- The findings offer a pathway to understanding and predicting exciton behavior.
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