while $ \sigma_{0} $ is the $ 2 \times 2 $ identity matrix. Typical values of the direction-dependent velocities, in units of $\left(\times 10^{5}\,m/s \right)$, are $ v_{x} = 19.58 $, $ v_{y} = 6.32 $, and $ v_{t} = -5.06 $. The corresponding energy dispersion of the Hamiltonian Eq. (\[boeqn\]), is analytically given by $$E^{\tau}\left(k\right) = \hbar v_{t}k_{x}+\tau \hbar\sqrt{v_{x}^{2}k_{x}^{2} + v_{y}^{2}k_{y}^{2}},
\label{diseq}$$

in which $\tau=$1(-1) denotes the conduction (valence) band in borophane dispersion. Isoenergy contour map of the electronic band structure of borophane in the $k-$space for $E(\vec{k}_{\rm F})=-0.5$ to $0.5$ eV, is shown in Fig.\[energyDispersion\](a).

Since several works on electronic properties of the 8-$ Pmmn $ borophene and borophane are available, a proper comparison with those results seems to be in order. Recent investigations, based on an [*ab initio*]{} evolutionary structure calculations [@X.-F.Zhou2016], show that the Fermi velocity value of the Dirac fermions in borophene is $v_F^x=0.56\times 10^{6}\,m/s $ in the $k_x$ direction, while for the $k_y$ direction it has two values of $v_F^y=0.46 \times 10^{6}\,m/s $ and $1.16 \times 10^{6}\,m/s $. For borophane, in the $k_x$ direction, the predicted Fermi velocities are $v_F^x=1.74$ and $0.97$, both in units of ($10^{6}\,m/s $). These values of the Fermi velocity 