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Renormalized Singles Green's Function for Quasi-Particle Calculations beyond the G0 W0 Approximation
Ye Jin1, Neil Qiang Su1, Weitao Yang1,2
1Department of Chemistry , Duke University , Durham , North Carolina 27708 , United States.
The Journal of Physical Chemistry Letters
|January 6, 2019
Summary
A new GRSW0 method improves quasi-particle energy calculations, overcoming limitations of standard G0W0 and expensive self-consistent GW methods. This approach enhances accuracy and reduces reliance on initial approximations for novel materials discovery.
Area of Science:
- Computational Materials Science
- Quantum Chemistry
- Condensed Matter Physics
Background:
- Accurate calculation of quasi-particle energies and band gaps is crucial for materials science.
- Standard density functional approximations (DFAs) often underestimate band gaps.
- The GW approximation offers improved accuracy but faces challenges with starting-point dependence (G0W0) and computational cost (self-consistent GW).
Purpose of the Study:
- To develop a simple, efficient, and accurate GRSW0 approach for calculating quasi-particle energies and band gaps.
- To reduce the dependence of GW calculations on the initial density functional approximation.
- To provide a more robust and reliable method for materials property prediction.
Main Methods:
- Developed a GRSW0 method involving subspace diagonalization of the Hartree-Fock Hamiltonian using the DFA density matrix.
- The GRS Green's function incorporates single excitation contributions to the self-energy.
- Applied the method to molecules and large band gap solids, comparing results with G0W0 and sc GW.
Main Results:
- The GRSW0 approach significantly improves upon G0W0 for molecules and large band gap solids.
- Demonstrated greatly reduced dependence on the initial DFA compared to G0W0.
- Observed improvements for other bulk materials, though to a lesser extent, potentially due to implementation limitations.
Conclusions:
- The GRSW0 method offers a robust and accurate alternative to existing GW approximations.
- Achieving good accuracy for band gaps does not necessitate the use of expensive hybrid DFAs.
- This work advances the reliability and applicability of the GW approximation in computational materials science.