论文标题
表面电荷引起的狄拉克带在电荷密度波材料中分裂（Tase4）2i
Surface Charge Induced Dirac Band Splitting in a Charge Density Wave Material (TaSe4)2I
论文作者
论文摘要
（Tase4）2i，一种准二维（1D）晶体，显示了特征温度驱动的金属 - 绝缘体相变。预测高于电荷密度波（CDW）温度TC，（Tase4）2i被预测具有weyl semimetal相。在TC下方，它成为轴线绝缘子。在这里，我们对（Tase4）2i的（110）表面进行了角度分辨光发射光谱（ARPES）测量，并在第一个光彩区观察到了两组类似Dirac的能带，这与我们的先季计算非常吻合。此外，我们发现，在某些情况下，每个狄拉克乐队都表现出数百个MEV的能量。结合核心水平测量值，我们的理论分析表明，由于表面碘原子的丧失，这种狄拉克带分裂是表面电荷极化的结果。我们在这里的发现为PEIERLS化合物中带拓扑与CDW顺序之间的相互作用提供了新的启示，并将激发更多有关强相关的准1D材料的拓扑特性的研究。
(TaSe4)2I, a quasi-one-dimensional (1D) crystal, shows a characteristic temperature-driven metal-insulator phase transition. Above the charge density wave (CDW) temperature Tc, (TaSe4)2I has been predicted to harbor a Weyl semimetal phase. Below Tc, it becomes an axion insulator. Here, we performed angle-resolved photoemission spectroscopy (ARPES) measurements on the (110) surface of (TaSe4)2I and observed two sets of Dirac-like energy bands in the first Brillion zone, which agree well with our first-principles calculations. Moreover, we found that each Dirac band exhibits an energy splitting of hundreds of meV under certain circumstances. In combination with core level measurements, our theoretical analysis showed that this Dirac band splitting is a result of surface charge polarization due to the loss of surface iodine atoms. Our findings here shed new light on the interplay between band topology and CDW order in Peierls compounds and will motivate more studies on topological properties of strongly correlated quasi-1D materials.
