Electronic excitations in semiconductors and insulators using the Sternheimer-GW method
<p>In this thesis we describe the extension and implementation of the Sternheimer- <em>GW</em> method to a first-principles pseudopotential framework based on a planewaves basis. The Sternheimer-GW method consists of calculating the <em>GW</em> self-energy operator with...
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| Формат: | Диссертация |
| Язык: | English |
| Опубликовано: |
2014
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| _version_ | 1826280465610309632 |
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| author | Lambert, H Henry Allen Robert Lambert |
| author2 | Giustino, F |
| author_facet | Giustino, F Lambert, H Henry Allen Robert Lambert |
| author_sort | Lambert, H |
| collection | OXFORD |
| description | <p>In this thesis we describe the extension and implementation of the Sternheimer- <em>GW</em> method to a first-principles pseudopotential framework based on a planewaves basis. The Sternheimer-GW method consists of calculating the <em>GW</em> self-energy operator without resorting to the standard expansion over unoccupied Kohn- Sham electronic states. The Green's function is calculated by solving linear systems for frequencies along the real axis. The screened Coulomb interaction is calculated for frequencies along the imaginary axis using the Sternheimer equa- tion, and analytically continued to the real axis. We exploit novel techniques for generating the frequency dependence of these operators, and discuss the imple- mentation and efficiency of the methodology.</p> <p>We benchmark our implementation by performing quasiparticle calculations on common insulators and semiconductors, including Si, diamond, LiCl, and SiC. Our calculated quasiparticle energies are in good agreement with the results of fully-converged calculations based on the standard sum-over-states approach and experimental data. We exploit the methodology to calculate the spectral func- tions for silicon and diamond and discuss quasiparticle lifetimes and plasmaronic features in these materials.</p> <p>We also exploit the methodology to perform quasiparticle calculations on the 2-dimensional transition metal dichalcogenide system molybdenum disulfide (MoS<sub>2</sub>). We compare the quasiparticle properties for bulk and monolayer MoS2 , and identify significant corrections at the <em>GW</em> level to the LDA bandstructure of these materials. We also discuss changes in the frequency dependence of the electronic screening in the bulk and monolayer systems and relate these changes to the quasiparticle lifetimes and spectral functions in the two limits. </p> |
| first_indexed | 2024-03-07T00:14:07Z |
| format | Thesis |
| id | oxford-uuid:7a3db604-b31d-4a87-b60a-65432b64e73a |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T00:14:07Z |
| publishDate | 2014 |
| record_format | dspace |
| spelling | oxford-uuid:7a3db604-b31d-4a87-b60a-65432b64e73a2022-03-26T20:42:42ZElectronic excitations in semiconductors and insulators using the Sternheimer-GW methodThesishttp://purl.org/coar/resource_type/c_db06uuid:7a3db604-b31d-4a87-b60a-65432b64e73aAtomic scale structure and propertiesMaterials modellingCondensed Matter PhysicsMaterials SciencesSiliconSemiconductorsEnglishOxford University Research Archive - Valet2014Lambert, HHenry Allen Robert LambertGiustino, F<p>In this thesis we describe the extension and implementation of the Sternheimer- <em>GW</em> method to a first-principles pseudopotential framework based on a planewaves basis. The Sternheimer-GW method consists of calculating the <em>GW</em> self-energy operator without resorting to the standard expansion over unoccupied Kohn- Sham electronic states. The Green's function is calculated by solving linear systems for frequencies along the real axis. The screened Coulomb interaction is calculated for frequencies along the imaginary axis using the Sternheimer equa- tion, and analytically continued to the real axis. We exploit novel techniques for generating the frequency dependence of these operators, and discuss the imple- mentation and efficiency of the methodology.</p> <p>We benchmark our implementation by performing quasiparticle calculations on common insulators and semiconductors, including Si, diamond, LiCl, and SiC. Our calculated quasiparticle energies are in good agreement with the results of fully-converged calculations based on the standard sum-over-states approach and experimental data. We exploit the methodology to calculate the spectral func- tions for silicon and diamond and discuss quasiparticle lifetimes and plasmaronic features in these materials.</p> <p>We also exploit the methodology to perform quasiparticle calculations on the 2-dimensional transition metal dichalcogenide system molybdenum disulfide (MoS<sub>2</sub>). We compare the quasiparticle properties for bulk and monolayer MoS2 , and identify significant corrections at the <em>GW</em> level to the LDA bandstructure of these materials. We also discuss changes in the frequency dependence of the electronic screening in the bulk and monolayer systems and relate these changes to the quasiparticle lifetimes and spectral functions in the two limits. </p> |
| spellingShingle | Atomic scale structure and properties Materials modelling Condensed Matter Physics Materials Sciences Silicon Semiconductors Lambert, H Henry Allen Robert Lambert Electronic excitations in semiconductors and insulators using the Sternheimer-GW method |
| title | Electronic excitations in semiconductors and insulators using the Sternheimer-GW method |
| title_full | Electronic excitations in semiconductors and insulators using the Sternheimer-GW method |
| title_fullStr | Electronic excitations in semiconductors and insulators using the Sternheimer-GW method |
| title_full_unstemmed | Electronic excitations in semiconductors and insulators using the Sternheimer-GW method |
| title_short | Electronic excitations in semiconductors and insulators using the Sternheimer-GW method |
| title_sort | electronic excitations in semiconductors and insulators using the sternheimer gw method |
| topic | Atomic scale structure and properties Materials modelling Condensed Matter Physics Materials Sciences Silicon Semiconductors |
| work_keys_str_mv | AT lamberth electronicexcitationsinsemiconductorsandinsulatorsusingthesternheimergwmethod AT henryallenrobertlambert electronicexcitationsinsemiconductorsandinsulatorsusingthesternheimergwmethod |