  We study the electronic and optical properties of single- and bilayer black
phosphorus with shortand long-range defects by using the tight-binding
propagation method. Both types of defect states are localized and induce a
strong scattering of conduction states reducing significantly the charge
carrier mobility. In contrast to properties of pristine samples, the anisotropy
of defect-induced optical excitations is suppressed due to the isotropic nature
of the defects. We also investigate the Landau level spectrum and
magneto-optical conductivity, and find that the discrete Landau levels are
sublinearly dependent on the magnetic field and energy level index, even at low
defect concentrations.
