  The Lifshitz theory of dispersion forces leads to thermodynamic and
experimental inconsistencies when the role of drifting charge carriers is
included in the model of the dielectric response. Recently modified reflection
coefficients were suggested that take into account screening effects and
diffusion currents. We demonstrate that this theoretical approach leads to a
violation of the third law of thermodynamics (Nernst's heat theorem) for a wide
class of materials and is excluded by the data from two recent experiments. The
physical reason for its failure is explained by the violation of thermal
equilibrium, which is the fundamental applicability condition of the Lifshitz
theory, in the presence of drift and diffusion currents.
