Efficient Full-frequency GW Calculations using a Lanczos Method
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arXiv
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| Autori principali: | , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2023
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| _version_ | 1866910378302111744 |
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| author | Gao, Weiwei Tang, Zhao Zhao, Jijun Chelikowsky, James R. |
| author_facet | Gao, Weiwei Tang, Zhao Zhao, Jijun Chelikowsky, James R. |
| contents | The GW approximation is widely used for reliable and accurate modeling of single-particle excitations. It also serves as a starting point for many theoretical methods, such as its use in the Bethe-Salpeter equation (BSE) and dynamical mean-field theory. However, full-frequency GW calculations for large systems with hundreds of atoms remain computationally challenging, even after years of efforts to reduce the prefactor and improve scaling. We propose a method that reformulates the correlation part of the GW self-energy as a resolvent of a Hermitian matrix, which can be efficiently and accurately computed using the standard Lanczos method. This method enables full-frequency GW calculations of material systems with a few hundred atoms on a single computing workstation. We further demonstrate the efficiency of the method by calculating the defect-state energies of silicon quantum dots with diameters up to 4 nm and nearly 2,000 silicon atoms using only 20 computational nodes. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2310_20103 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Efficient Full-frequency GW Calculations using a Lanczos Method Gao, Weiwei Tang, Zhao Zhao, Jijun Chelikowsky, James R. Computational Physics Materials Science Other Condensed Matter The GW approximation is widely used for reliable and accurate modeling of single-particle excitations. It also serves as a starting point for many theoretical methods, such as its use in the Bethe-Salpeter equation (BSE) and dynamical mean-field theory. However, full-frequency GW calculations for large systems with hundreds of atoms remain computationally challenging, even after years of efforts to reduce the prefactor and improve scaling. We propose a method that reformulates the correlation part of the GW self-energy as a resolvent of a Hermitian matrix, which can be efficiently and accurately computed using the standard Lanczos method. This method enables full-frequency GW calculations of material systems with a few hundred atoms on a single computing workstation. We further demonstrate the efficiency of the method by calculating the defect-state energies of silicon quantum dots with diameters up to 4 nm and nearly 2,000 silicon atoms using only 20 computational nodes. |
| title | Efficient Full-frequency GW Calculations using a Lanczos Method |
| topic | Computational Physics Materials Science Other Condensed Matter |
| url | https://arxiv.org/abs/2310.20103 |