  We consider a massive fermionic quantum field localized on a plane in
external constant and homogeneous electric and magnetic fields. The magnetic
field is perpendicular to the plane and the electric field is parallel. The
complete set of solutions to the Dirac equation is presented. As important
physical characteristics of the vacuum state, the fermion condensate and the
expectation value of the energy-momentum tensor are investigated. The
renormalization is performed using the Hurwitz function. The results are
compared with those previously studied in the case of zero electric field. We
discuss the behavior of the vacuum expectation values in different regions for
the values of the problem parameters. Applications of the results include the
electronic subsystem of graphene sheet described by the Dirac model in the
long-wavelength approximation.
