Ambient pressure Dirac electron system in quasi-two-dimensional molecular conductor ${\alpha}$-(BETS)$_2$I$_3$
| Autor: | Kitou, Shunsuke, Tsumuraya, Takao, Sawahata, Hikaru, Ishii, Fumiyuki, Hiraki, Ko-ichi, Nakamura, Toshikazu, Katayama, Naoyuki, Sawa, Hiroshi |
|---|---|
| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | Phys. Rev. B 103, 035135 (2021) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.103.035135 |
| Popis: | We investigated the precise crystal structures and electronic states in a quasi-two-dimensional molecular conductor ${\alpha}$-(BETS)$_2$I$_3$ at ambient pressure. The electronic resistivity of this molecular solid shows metal-to-insulator (MI) crossover at $T_{MI}$=50 K. Our x-ray diffraction and $^{13}$C nuclear magnetic resonance experiments revealed that ${\alpha}$-(BETS)$_2$I$_3$ maintains the inversion symmetry below $T_{MI}$. First-principles calculations found a pair of anisotropic Dirac cones at a general k-point, with the degenerate contact points at the Fermi level. The origin of the insulating state in this system is a small energy gap of ~2 meV opened by the spin-orbit interaction. The Z$_2$ topological invariants indicate that this system is a weak topological insulator. Our results suggest that ${\alpha}$-(BETS)$_2$I$_3$ is a promising material for studying the bulk Dirac electron system in two dimensions. Comment: 9 pages, 6 figures + Supplemental Material |
| Databáze: | arXiv |
| Externí odkaz: |
|