Stochastic time-dependent DFT with optimally tuned range-separated hybrids: Application to excitonic effects in large...

Area of Science:

• Computational Chemistry
• Materials Science
• Quantum Mechanics

Background:

• Calculating optical spectra is crucial for understanding material properties.
• Exciton formation significantly influences optical spectra.
• Existing methods can be computationally expensive.

Purpose of the Study:

• To develop an efficient stochastic approach for time-dependent density functional theory (TD-DFT).
• To accurately calculate optical spectra, including exciton effects.
• To enable the study of larger and more complex material systems.

Main Methods:

• A stochastic approach to TD-DFT using optimally tuned range-separated hybrids.
• Inclusion of electron-hole interaction via time-dependent linear-response.
• Efficient computation of nonlocal exchange through a stochastic scheme.

Main Results:

• The developed method accurately calculates optical spectra.
• Results show excellent agreement with experimental data.
• The approach scales quadratically with electron number, offering significant efficiency gains.

Conclusions:

• The stochastic TD-DFT method provides an efficient and accurate way to compute optical spectra.
• This method effectively captures exciton effects.
• Demonstrated applicability on large phosphorene sheets highlights its potential for complex materials.