  Chemical modification, such as intercalation or doping of novel materials is
of great importance for exploratory material science and applications in
various fields of physics and chemistry. In the present work, we report the
systematic intercalation of chemically exfoliated few-layer graphene with
potassium while monitoring the sample resistance using microwave conductivity.
We find that the conductivity of the samples increases by about an order of
magnitude upon potassium exposure. The increased of number of charge carriers
deduced from the ESR intensity also reflects this increment. The doped phases
exhibit two asymmetric Dysonian lines in ESR, a usual sign of the presence of
mobile charge carriers. The width of the broader component increases with the
doping steps, however, the narrow components seem to have a constant line
width.

Materials Science;Strongly Correlated Electrons