Substrate effect on excitonic shift and radiative lifetime of two-dimensional materials

Area of Science:

• Condensed Matter Physics
• Materials Science
• Computational Physics

Background:

• Two-dimensional (2D) materials exhibit unique optoelectronic properties influenced by substrates.
• Accurate theoretical methods are crucial for understanding substrate effects at 2D interfaces.
• Previous work introduced a reciprocal-space linear interpolation method for substrate screening at the GW level.

Purpose of the Study:

• To investigate substrate effects on excitonic excitation and recombination in 2D materials.
• To elucidate the physical mechanisms behind substrate-induced changes in electronic properties.
• To calculate exciton radiative lifetimes for specific 2D materials on various substrates.

Main Methods:

• Application of the reciprocal-space linear interpolation method.
• Solving the Bethe-Salpeter equation to study excitonic properties.
• Utilizing a 2D hydrogen model to analyze underlying physics.

Main Results:

• Predicted nonrigid shifts in excitonic peaks, consistent with experimental data.
• Revealed a linear relationship between quasiparticle gaps and exciton binding energies.
• Calculated exciton radiative lifetimes for hexagonal boron nitride and WS2, showing good agreement with experiments.

Conclusions:

• The developed method accurately captures substrate screening effects on 2D material optoelectronics.
• Understanding substrate interactions is key to tailoring 2D material applications.
• This work provides a theoretical framework for predicting and interpreting experimental observations.