Ultrafast Spectroscopy of Dirac Semimetal Cd3As2 under Pressure
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| Format: | Preprint |
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2024
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| _version_ | 1866910849294139392 |
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| author | Arora, Vikas Muthu, D. V. S. Sankar, R Sood, A K |
| author_facet | Arora, Vikas Muthu, D. V. S. Sankar, R Sood, A K |
| contents | Topological properties of a three-dimensional Dirac semimetal Cd3As2, protected by crystal rotation and time-reversal symmetry, can be tuned with the application of pressure. Ultrafast spectroscopy is a unique tool to investigate the character and time evolution of electronic states, emphasizing the signatures of transition. We designed an experimental setup for in-situ pressure-dependent ultrafast optical pump optical probe spectroscopy of Cd3As2 using a symmetric diamond anvil cell. The fast relaxation processes show significant changes across pressure-induced phase transitions at PC1, approximately 3 GPa, and PC2, approximately 9 GPa. A new sub-picosecond time scale relaxation dynamics emerges beyond PC2. Theoretical calculations of differential reflectivity for both interband and intraband processes indicate that the negative (positive) differential reflectivity (Delta R/R) results from the interband (intraband) processes. The pressure-dependent behavior of relaxation dynamics amplitudes beyond PC1 emphasized the necessity of incorporating quadratic band opening in the calculations, explaining the transition of Cd3As2 from a Dirac semimetal to a semiconducting phase. The time evolution of differential reflectivity is calculated using the electronic temperature as a function of time, as provided by the two-temperature model, which fits the experimental data. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2411_15791 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Ultrafast Spectroscopy of Dirac Semimetal Cd3As2 under Pressure Arora, Vikas Muthu, D. V. S. Sankar, R Sood, A K Materials Science Topological properties of a three-dimensional Dirac semimetal Cd3As2, protected by crystal rotation and time-reversal symmetry, can be tuned with the application of pressure. Ultrafast spectroscopy is a unique tool to investigate the character and time evolution of electronic states, emphasizing the signatures of transition. We designed an experimental setup for in-situ pressure-dependent ultrafast optical pump optical probe spectroscopy of Cd3As2 using a symmetric diamond anvil cell. The fast relaxation processes show significant changes across pressure-induced phase transitions at PC1, approximately 3 GPa, and PC2, approximately 9 GPa. A new sub-picosecond time scale relaxation dynamics emerges beyond PC2. Theoretical calculations of differential reflectivity for both interband and intraband processes indicate that the negative (positive) differential reflectivity (Delta R/R) results from the interband (intraband) processes. The pressure-dependent behavior of relaxation dynamics amplitudes beyond PC1 emphasized the necessity of incorporating quadratic band opening in the calculations, explaining the transition of Cd3As2 from a Dirac semimetal to a semiconducting phase. The time evolution of differential reflectivity is calculated using the electronic temperature as a function of time, as provided by the two-temperature model, which fits the experimental data. |
| title | Ultrafast Spectroscopy of Dirac Semimetal Cd3As2 under Pressure |
| topic | Materials Science |
| url | https://arxiv.org/abs/2411.15791 |