Theoretical study of short-range exchange interaction based on semiconductor dielectric function model toward...

Area of Science:

• Condensed matter physics
• Computational materials science
• Quantum chemistry

Background:

• Semiconductor dielectric functions are crucial for understanding electronic properties.
• Screened exchange interactions and their short-range effects are key to accurate material modeling.
• Existing dielectric density functional theory (DFT) methods require refinement for short-range interactions.

Purpose of the Study:

• To develop and validate a modified dielectric DFT framework accounting for dielectric-dependent short-range exchange.
• To investigate the influence of the high wavenumber spectrum on short-range exchange effects.
• To assess the performance of the time-dependent dielectric DFT method for excited states.

Main Methods:

• Derivation of screened exchange interaction focusing on the large wavenumber spectrum.
• Incorporation of local Slater and Yukawa-type terms into the dielectric DFT framework.
• Adjustment of term ratios based on the system's dielectric constant.
• Application of time-dependent dielectric DFT for excited-state calculations.

Main Results:

• The short-range effect of the screened exchange potential is shown to be dependent on the dielectric constant.
• A method is proposed to integrate dielectric-dependent short-range effects into DFT using adjustable terms.
• The time-dependent dielectric DFT method accurately characterizes excited electronic structures in dyes and functional molecules.

Conclusions:

• The developed approach effectively models dielectric-dependent short-range exchange interactions.
• The findings provide a more accurate theoretical tool for electronic structure calculations.
• This work offers valuable insights for theoretical studies on exchange interactions in various systems.