Coexistence of open and closed type nodal line topological semimetals in two dimensional B2C
Coexistence of open and closed type nodal line topological semimetals in two dimensional B2C
复制标题
二维B2C中开闭型节点线拓扑半金属的共存
DOI：
10.1039/c7tc05095j
复制
发表时间：
2018-02
影响因子：
6.4
通讯作者：
孙立忠
中科院分区：
文献类型：
--
作者：
周攀;马增胜;孙立忠
拓扑半金属，包括Dirac半金属、Weyl半金属和节线半金属，由于其内在的拓扑性质和迷人的性质而引起了人们极大的研究兴趣。利用密度泛函理论（DFT），我们发现节线半金属和Dirac半金属可以共存于二维B_2C单层膜的低能电子中。有趣的是，除了I型和II型狄拉克费米子外，费米能级周围还出现了一种开放的节线。B2C片层的低能电子性质可以使用紧束缚（TB）模型来描述，该模型依赖于B-py，pz和C-py，pz状态的基础。该系统的一个重要优点是这四种拓扑半金属的能量窗口不同，在实验中很容易区分。该系统为研究不同类型半金属间的相互作用提供了良好的平台。
Topological semimetals, including Dirac semimetals, Weyl semimetals, and nodal line semimetals, receive enormous research interest due to their intrinsic topological nature and fascinating properties. In the present work, with the help of density functional theory (DFT), we find that nodal line semimetals and Dirac semimetals can coexist in the low energy electron of a two dimensional (2D) B2C monolayer. Intriguingly, besides type-I and type-II Dirac fermions, a kind of open nodal line appears around the Fermi level. The low energy electronic nature of the B2C sheet can be described using a tight-binding (TB) model that relies on the basis of B-py, pz and C-py, pz states. One of the important merits of the system is that the energy windows of these four types of topological semimetals are different which can be easily distinguished in experiments. Moreover, the system provides an excellent platform for studying the interplay between different type semimetals.