Dependence of mobility on the electron concentration upon scattering at polar optical phonons in A$^{\mathrm{III}}$N nitrides

The dependence of the effective relaxation time on the electron concentration in A$^{\mathrm{III}}$N nitrides in the case of electron scattering at polar longitudinal optical phonons is calculated by the marching method. The method takes into account the inelasticity of electron scattering at polar optical phonons for nitrides in the zinc-blende approximation. The calculations show a substantial increase in mobility in samples with a degenerate electron gas, if screening of the long-range potential of polar longitudinal optical phonons is taken into account.