The Dirac point and cones make some two-dimensional materials ( e.g., graphene, silicone and graphyne) exhibit ballistic charge transport and enormously high carrier mobilities. Here, we present a novel semimetal with triangular lattice. Metallic BeB2 monolayer could transform to a semimetal with a Dirac point at the Fermi level when the lattice parameters are isotropically compressed by about 5%, while it becomes metallic again under larger compression. The Fermi velocity of semimetallic BeB2 monolayer is 0.857 x 10(6) m s(-1), just a little smaller than that of graphene. Furthermore, it is found that uniaxial compressive strain opens a band gap in the BeB2 monolayer, while uniaxial tensile strain keeps it metallic. Our study expands the Dirac systems and provides new insight to explore novel semimetallic materials.
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机译:狄拉克点和锥使一些二维材料(例如石墨烯,硅树脂和石墨烯)表现出弹道电荷传输和极高的载流子迁移率。在这里,我们提出了一种具有三角晶格的新型半金属。当将晶格参数各向同性压缩约5%时,金属BeB2单层可以转变为狄拉克点在费米能级的半金属,而在较大压缩下再次变为金属。半金属BeB2单层的费米速度为0.857 x 10(6)m s(-1),仅比石墨烯小。此外,发现单轴压缩应变在BeB2单层中打开了一个带隙,而单轴拉伸应变使它保持金属状态。我们的研究扩展了Dirac系统,并为探索新型半金属材料提供了新的见识。
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