quasi-particle self-consistent

The quasi-particle self-consistent (QSGW) method is an advanced computational technique used in condensed matter physics and materials science to calculate the electronic properties of materials. It improves upon the standard approximation by iteratively updating the one-particle (quasi-particle) Hamiltonian . This method provides more accurate quasi-particle energies and electronic band structures compared to traditional density functional theory (DFT) calculations.

Key features of QSGW:

• Self-consistent scheme
• Improved accuracy in predicting electronic properties.
• Applicable to a wide range of materials, including semiconductors, insulators, and metals.

WARNING

QSGW does NOT directly update the one-particle Green's function but does so through the one-particle Hamiltonian. The former method is known as self-consistent , but it is also known as a less accurate method due to the neglect of vertex corrections.

where

• : Kinetic energy term
• : External potential
• : Hartree term (Coulomb interaction between electrons)
• : Exchange-correlation potential

in the QSGW, one-particle Hamiltonian is constracted by following formula

Flowchart

This flowchart outlines the process of obtaining the GW self-energy and the QSGW potential . It starts with solving a one-particle equation to get , followed by determining the its eigenvalues and eigenfunctions. The process then branches into calculating core-exchange self-energy , exchange self-energy , and correlation self-energy , which are combined to obtain the self-energy and the QSGW potential . The cycle continues until the condition is met.