Topological Semimetal KAlGe with Novel Electronic Instability
| Autor: | Ikenobe, Toshiya, Yamada, Takahiro, Yamaura, Jun-ichi, Oguchi, Tamio, Okuma, Ryutaro, Hirai, Daigorou, Sagayama, Hajime, Okamoto, Yoshihiko, Hiroi, Zenji |
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| Rok vydání: | 2024 |
| Předmět: | |
| Zdroj: | Chemistry of Materials, 2024 |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1021/acs.chemmater.4c02284 |
| Popis: | Compounds with the anti-PbFCl structure exhibit a variety of electronic instabilities and intriguing physical properties. NaAlSi and NaAlGe are similar topological nodal-line semimetals, but they have distinct properties. NaAlSi is a superconductor at 6.8 K, whereas NaAlGe is an insulator with a pseudogap of approximately 100 K. Using the potassium-indium flux method, we succeeded in synthesizing a single crystal of KAlGe, a new anti-PbFCl compound. First principles electronic structure calculations reveal that KAlGe is isoelectronic with NaAlSi and NaAlGe. KAlGe undergoes a metal-to-metal transition at 89 K and exhibits no superconductivity above 1.8 K. The low temperature phase has significantly lower carrier density and extremely high mobility, similar to Dirac electron systems. Furthermore, X-ray diffraction experiments show a structural change that breaks the fourfold symmetry during the phase transition. Electron-phonon interactions may be responsible for superconductivity in NaAlSi, whereas excitonic electron-hole interactions are thought to play an important role in KAlGe and possibly NaAlGe. Our findings demonstrate that fascinating physics lies within the compound family. Comment: 12 pages, 12 figures, accepted by Chemistry of Materials |
| Databáze: | arXiv |
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