论文标题
对称性保证二维的零dirac-line半学，以与强旋轨耦合
Symmetry guaranteed Dirac-line semimetals in two-dimensions against strong spin-orbit coupling
论文作者
论文摘要
在三维Dirac节点线半光（3D-DNLSM）中发现了几种有趣的电子现象和电性能，但是，在强的自旋轨道耦合（SOC）下很容易受到干扰。虽然二维（2D）层是具有许多优势的新兴材料类别，但针对SOC的2D-DNLSM尚待发现。 Here, we report a 2D-DNLSM in odd-atomic-layer Bi (the brick phase, another Bi allotrope), whose robustness against SOC is protected by the little co-group C_2v \times Z^T_2, the unique protecting symmetry we found in 2D.Specially, (4n+2) valence electrons fill the electronic bands in the brick phase, so that the Dirac nodal line with fourfold退化位于费米水平。几乎没有其他低能状态接近费米水平。这允许在不受其他频段影响的情况下可行地观察到运输测量中的巧妙DNLSM诱导的现象。相比之下，其他VA组元素也形成了砖阶段，但其DNL状态与费米水平附近的额外状态混合在一起。这种前所未有的分层材料类别允许在2D中探索几乎孤立的2DDNL状态。
Several intriguing electronic phenomena and electric properties were discovered in three-dimensional Dirac nodal line semimetals (3D-DNLSM), which are, however, easy to be perturbed under strong spin-orbit coupling (SOC). While two-dimensional (2D) layers are an emerging material category with many advantages, 2D-DNLSM against SOC is yet to be uncovered. Here, we report a 2D-DNLSM in odd-atomic-layer Bi (the brick phase, another Bi allotrope), whose robustness against SOC is protected by the little co-group C_2v \times Z^T_2, the unique protecting symmetry we found in 2D.Specially, (4n+2) valence electrons fill the electronic bands in the brick phase, so that the Dirac nodal line with fourfold degeneracy locates across the Fermi level. There are almost no other low energy states close to the Fermi level; this allows to feasibly observe the neat DNLSM-induced phenomena in transport measurements without being affected by other bands. In contrast, Other VA-group elements also form the brick phases, but their DNL states are mixed with the extra states around the Fermi level. This unprecedented category of layered materials allows for exploring nearly isolated 2DDNL states in 2D.
