import matplotlib.pyplot as plt
from graphenemodeling.graphene import monolayer as mlg
from scipy.constants import elementary_charge as eV
eF = 0.4*eV
kF = mlg.FermiWavenumber(eF,model='LowEnergy')
k = np.linspace(-2*kF,2*kF,num=100)
conduction_band = mlg.CarrierDispersion(k,model='LowEnergy')
valence_band = mlg.CarrierDispersion(k,model='LowEnergy',eh=-1)
fig, ax = plt.subplots(figsize=(5,6))
ax.plot(k/kF,conduction_band/eF,'k')
# [...
ax.plot(k/kF,valence_band/eF, 'k')
# [...
ax.plot(k/kF,np.zeros_like(k),color='gray')
# [...
ax.axvline(x=0,ymin=0,ymax=1,color='gray')
# <...
ax.set_axis_off()
plt.show()