| Autor: |
Mazza, Giacomo, Rösner, Malte, Windgätter, Lukas, Latini, Simone, Hübener, Hannes, Millis, Andrew J., Rubio, Angel, Georges, Antoine |
| Rok vydání: |
2019 |
| Předmět: |
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| Zdroj: |
Phys. Rev. Lett. 124, 197601 (2020) |
| Druh dokumentu: |
Working Paper |
| DOI: |
10.1103/PhysRevLett.124.197601 |
| Popis: |
Ta$_2$NiSe$_5$ is one of the most promising materials for hosting an excitonic insulator ground state. While a number of experimental observations have been interpreted in this way, the precise nature of the symmetry breaking occurring in Ta$_2$NiSe$_5$, the electronic order parameter, and a realistic microscopic description of the transition mechanism are, however, missing. By a symmetry analysis based on first-principles calculations, we uncover the \emph{discrete} lattice symmetries which are broken at the transition. We identify a purely electronic order parameter of excitonic nature that breaks these discrete crystal symmetries and contributes to the experimentally observed lattice distortion from an orthorombic to a monoclinic phase. Our results provide a theoretical framework to understand and analyze the excitonic transition in Ta$_2$NiSe$_5$ and settle the fundamental questions about symmetry breaking governing the spontaneous formation of excitonic insulating phases in solid-state materials. |
| Databáze: |
arXiv |
| Externí odkaz: |
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