Time-Resolved Exciton Wave Functions from Time-Dependent Density-Functional Theory.

Area of Science:

• Computational materials science
• Quantum chemistry
• Condensed matter physics

Background:

• Time-dependent density-functional theory (TDDFT) is a key method for calculating optical spectra.
• TDDFT efficiently includes excitonic effects in insulators and semiconductors.
• Understanding exciton dynamics is crucial for materials science.

Purpose of the Study:

• To present a method for obtaining exciton wave functions from TDDFT.
• To demonstrate the application of this method in both frequency-dependent and real-time TDDFT.
• To explore the real-time dynamics of exciton formation and dissociation.

Main Methods:

• Utilizing the Kohn-Sham transition density matrix within TDDFT.
• Applying the method in the frequency-dependent linear-response regime.
• Implementing the method via real-time propagation simulations.

Main Results:

• Exciton wave functions were successfully extracted from TDDFT calculations.
• The approach was validated using one-dimensional model solids.
• Real-time simulations provided insights into exciton formation and dissociation processes.

Conclusions:

• The developed TDDFT approach enables the calculation of exciton wave functions.
• This method facilitates real-time studies of exciton dynamics in materials.
• Real-time TDDFT is a powerful tool for investigating excited-state phenomena.