  We find the low-temperature behavior of the Casimir-Polder free energy and
entropy for an atom interacting with real graphene sheet possessing nonzero
energy gap and chemical potential. Employing the formalism of the polarization
tensor, it is shown that the Casimir-Polder entropy goes to zero by the power
law with vanishing temperature, i.e., the Nernst heat theorem is satisfied.
This result is discussed in connection with the problems connected with account
of free charge carriers in the Lifshitz theory.
