Optical conductivity and band gap in the double-Weyl candidate SrSi2 at ambient pressure
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arXiv
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| Format: | Preprint |
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2025
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| author | Maulana, L. Z. Tsirlin, A. A. Uykur, E. Saito, Y. Dressel, M. Imai, M. Pronin, A. V. |
| author_facet | Maulana, L. Z. Tsirlin, A. A. Uykur, E. Saito, Y. Dressel, M. Imai, M. Pronin, A. V. |
| contents | We probe the possible double-Weyl state in cubic SrSi2 using optical spectroscopy. The complex optical conductivity was measured in a frequency range from 70 to 22 000 cm-1 at temperatures down to 10 K at ambient pressure. The optical response of SrSi2 can be well separated into the intraband (free carriers) and interband contributions. Additionally, four infrared-active phonons are detected. As follows from the optical spectra, the free-carrier density decreases with decreasing temperature, consistent with an activation behaviour. Experimental interband conductivity juxtaposed with ab initio calculations shows that conventional density-functional theory fails to describe the electronic structure of SrSi2 in the vicinity of the Fermi level. A semi-local exchange-correlation potential allows a much better agreement with the experiment, resulting in the trivial (gapped) band structure of SrSi2. The direct gap estimated from the measurements is approximately 40 meV. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2510_04266 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Optical conductivity and band gap in the double-Weyl candidate SrSi2 at ambient pressure Maulana, L. Z. Tsirlin, A. A. Uykur, E. Saito, Y. Dressel, M. Imai, M. Pronin, A. V. Mesoscale and Nanoscale Physics Materials Science We probe the possible double-Weyl state in cubic SrSi2 using optical spectroscopy. The complex optical conductivity was measured in a frequency range from 70 to 22 000 cm-1 at temperatures down to 10 K at ambient pressure. The optical response of SrSi2 can be well separated into the intraband (free carriers) and interband contributions. Additionally, four infrared-active phonons are detected. As follows from the optical spectra, the free-carrier density decreases with decreasing temperature, consistent with an activation behaviour. Experimental interband conductivity juxtaposed with ab initio calculations shows that conventional density-functional theory fails to describe the electronic structure of SrSi2 in the vicinity of the Fermi level. A semi-local exchange-correlation potential allows a much better agreement with the experiment, resulting in the trivial (gapped) band structure of SrSi2. The direct gap estimated from the measurements is approximately 40 meV. |
| title | Optical conductivity and band gap in the double-Weyl candidate SrSi2 at ambient pressure |
| topic | Mesoscale and Nanoscale Physics Materials Science |
| url | https://arxiv.org/abs/2510.04266 |