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arXiv 2006.08978cond-mat.str-el
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准二维分子导体$α$ -(BETS)$_2$ I $_3$中的常压狄拉克电子系统

Ambient pressure Dirac electron system in quasi-two-dimensional molecular conductor $α$-(BETS)$_2$I$_3$

Shunsuke Kitou, Takao Tsumuraya, Hikaru Sawahata, Fumiyuki Ishii, Ko-ichi Hiraki, Toshikazu Nakamura, Naoyuki Katayama, Hiroshi Sawa

摘要:

研究了准二维分子导体$α$ -(BETS)$_2$ I $_3$在常压下的精确晶体结构和电子态.该分子固体的电子电阻率在$T_{MI}$ =50 K时显示出金属-绝缘体(MI)交叉。我们的X射线衍射和$^{13}$ C核磁共振实验表明,$α$ -(BETS)$_2$ I $_3$保持低于$T_{MI}$的反转对称性。第一性原理计算发现了一对各向异性的狄拉克锥在一般的k点,与费米能级的简并接触点。在这个系统中的绝缘状态的起源是一个小的能隙~2 meV的自旋轨道相互作用打开。Z $_2$拓扑不变量表明该系统是一个弱拓扑绝缘体。结果表明,$α$ -(BETS)$_2$ I $_3$是一种很有前途的研究二维Dirac电子体系的材料.

英文摘要:

We investigated the precise crystal structures and electronic states in a quasi-two-dimensional molecular conductor $α$-(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 $α$-(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 $α$-(BETS)$_2$I$_3$ is a promising material for studying the bulk Dirac electron system in two dimensions.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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