Borophane: Stable Two-dimensional Anisotropic Dirac Material with   Ultrahigh Fermi Velocity
  Recent synthesis of monolayer borophene (triangle boron monolayer) on the substrate opens the era of boron nanosheet (Science, 350, 1513, $\mathbf{2015}$), but the structural stability and novel physical properties are still open issues. Here we demonstrated borophene can be stabilized with fully surface hydrogenation, called as borophane, from first-principles calculations. Most interesting, it shows that borophane has direction-dependent Dirac cones, which are mainly contributed by in-plane \emph{p$_{x}$} and \emph{p$_{y}$} orbitals of boron atoms. The Dirac fermions possess an ultrahigh Fermi velocity up to 3.0$\times$10$^{6}$ m/s, 4 times higher than that of graphene. The Young's modules are calculated to be 129 and 200 GPa$\cdot$nm along two different directions, which is comparable with steel. The ultrahigh Fermi velocity and high mechanical feature render borophane ideal for nanoelectronics applications. 
Lichun Xu, Aijun Du and Liangzhi Kou
cond-mat.mtrl-sci