Accelerating GW Calculations of Point Defects with the Defect-Patched Screening Approximation

Area of Science:

• Computational materials science
• Quantum chemistry
• Solid-state physics

Background:

• The GW approximation is a key tool for calculating defect levels, incorporating many-electron effects.
• High computational cost limits GW calculations, especially for low-density defects requiring large supercells.

Purpose of the Study:

• To accelerate GW calculations for point defects by optimizing the many-electron screening step.
• To develop a more efficient method for modeling defect-induced screening.

Main Methods:

• Decomposing the random-phase approximation screening into intrinsic and defect-induced components.
• Calculating intrinsic screening using pristine unit cells and defect screening with smaller supercells and energy windows.
• Applying the defect-patched screening approach to various neutral and charged point defects in 2D and bulk materials.

Main Results:

• The proposed method significantly reduces simulation costs compared to direct GW calculations.
• Results obtained using the defect-patched screening approach show excellent agreement with direct GW simulations.
• The method successfully models defects in systems with varying bandgaps.

Conclusions:

• The defect-patched screening approach offers a computationally efficient alternative for GW calculations of point defects.
• This method clarifies the role of defects in many-electron screening.
• Enables rapid screening of defect structures for applications in quantum technologies like single-photon sources and qubits.