Convergence analysis of the thermal discrete dipole approximation

Area of Science:

• Physics
• Thermodynamics
• Computational Electromagnetics

Background:

• Near-field radiative heat transfer is crucial for nanoscale devices.
• The thermal discrete dipole approximation (T-DDA) is a method for simulating this transfer.
• Understanding T-DDA convergence is essential for accurate simulations.

Purpose of the Study:

• Investigate the convergence of the T-DDA method.
• Quantify T-DDA errors for various parameters.
• Evaluate the effectiveness of nonuniform discretization.

Main Methods:

• Comparing T-DDA results with exact solutions for two-sphere systems.
• Analyzing T-DDA errors based on sphere size, refractive index, and gap thickness.
• Implementing and assessing a nonuniform discretization scheme.

Main Results:

• T-DDA accuracy decreases with higher refractive indices and sphere diameter-to-gap ratios.
• Increasing subvolume count improves T-DDA convergence.
• Nonuniform discretization significantly speeds up convergence and reduces errors.

Conclusions:

• Nonuniform discretization is recommended for efficient and accurate near-field thermal radiation simulations.
• T-DDA demonstrates high accuracy, especially with surface polariton effects.
• The T-DDA method, with optimized discretization, is a reliable tool for complex thermal transport studies.