Non-excitonic mechanism for electronic and structural phase transitions in Ta2Ni(Se,S)5
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arXiv
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| Main Authors: | , , , , |
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| Format: | Preprint |
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2025
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| _version_ | 1866915505525227520 |
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| author | Tang, Weichen Li, Zhenglu Chen, Cheng He, Yu Louie, Steven G. |
| author_facet | Tang, Weichen Li, Zhenglu Chen, Cheng He, Yu Louie, Steven G. |
| contents | We present a first-principles study based on density functional theory (DFT) on the electronic and structural properties of Ta2NiSe5, a layered transition metal chalcogenide that has been considered as a possible candidate for an excitonic insulator. Our systematic DFT results however provide a non-excitonic mechanism for the experimentally observed electronic and structural phase transitions in Ta2NiSe5, in particular explaining why sulfur substitution of selenium reduces the distortion angle in the low-temperature phase and potassium dosing closes the gap in the electronic structure. Moreover, the calculations show that these two effects couple to each other. Further, our first-principles calculations predict several changes in both the crystal structure and electronic structure under the effects of uniform charge dosing and uniaxial strain, which could be tested experimentally. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2505_17324 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Non-excitonic mechanism for electronic and structural phase transitions in Ta2Ni(Se,S)5 Tang, Weichen Li, Zhenglu Chen, Cheng He, Yu Louie, Steven G. Materials Science We present a first-principles study based on density functional theory (DFT) on the electronic and structural properties of Ta2NiSe5, a layered transition metal chalcogenide that has been considered as a possible candidate for an excitonic insulator. Our systematic DFT results however provide a non-excitonic mechanism for the experimentally observed electronic and structural phase transitions in Ta2NiSe5, in particular explaining why sulfur substitution of selenium reduces the distortion angle in the low-temperature phase and potassium dosing closes the gap in the electronic structure. Moreover, the calculations show that these two effects couple to each other. Further, our first-principles calculations predict several changes in both the crystal structure and electronic structure under the effects of uniform charge dosing and uniaxial strain, which could be tested experimentally. |
| title | Non-excitonic mechanism for electronic and structural phase transitions in Ta2Ni(Se,S)5 |
| topic | Materials Science |
| url | https://arxiv.org/abs/2505.17324 |