Four-electron Negative-U Vacancy Defects in Antimony Selenide
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arXiv
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| Hauptverfasser: | , , , |
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| Format: | Preprint |
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2023
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| _version_ | 1866909170888867840 |
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| author | Wang, Xinwei Kavanagh, Sean R. Scanlon, David O. Walsh, Aron |
| author_facet | Wang, Xinwei Kavanagh, Sean R. Scanlon, David O. Walsh, Aron |
| contents | The phenomenon of negative-U behavior, where a defect traps a second charge carrier more strongly than the first, has been established in many host crystals. Here we report the case of four-carrier transitions for both vacancy defects in Sb2Se3. A global structure searching strategy is employed to explore the defect energy landscape from first-principles, revealing previously-unrealized configurations which facilitate a major charge redistribution. Thermodynamic analysis of the accessible charge states reveals a four-electron negative-U transition (delta q = 4) for both V_Se and V_Sb and, by consequence, amphoteric behavior for all intrinsic defects in Sb2Se3, with impact on its usage in solar cells. To the best of our knowledge, four-electron negative-U behavior has not been previously explored in this or other compounds. The unusual behavior is facilitated by valence alternation, a reconfiguration of the local bonding environments, characteristic of both Se and Sb. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2302_04901 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Four-electron Negative-U Vacancy Defects in Antimony Selenide Wang, Xinwei Kavanagh, Sean R. Scanlon, David O. Walsh, Aron Materials Science Computational Physics The phenomenon of negative-U behavior, where a defect traps a second charge carrier more strongly than the first, has been established in many host crystals. Here we report the case of four-carrier transitions for both vacancy defects in Sb2Se3. A global structure searching strategy is employed to explore the defect energy landscape from first-principles, revealing previously-unrealized configurations which facilitate a major charge redistribution. Thermodynamic analysis of the accessible charge states reveals a four-electron negative-U transition (delta q = 4) for both V_Se and V_Sb and, by consequence, amphoteric behavior for all intrinsic defects in Sb2Se3, with impact on its usage in solar cells. To the best of our knowledge, four-electron negative-U behavior has not been previously explored in this or other compounds. The unusual behavior is facilitated by valence alternation, a reconfiguration of the local bonding environments, characteristic of both Se and Sb. |
| title | Four-electron Negative-U Vacancy Defects in Antimony Selenide |
| topic | Materials Science Computational Physics |
| url | https://arxiv.org/abs/2302.04901 |