  In this paper, the single-particle-reduced entropy of a nanowire field-effect
transistor (NWFET) in the Coulomb blockade regime is studied by means of a
multi-configurational self-consistent Green's function approach. Assuming that
the many-body statistical preparation of the system is described by a mixture
of Slater determinants of relevant natural orbitals, the
single-particle-reduced entropy can be interpreted as a measure of the degree
of mixture of the system's preparation. Considering the realistic case of an
InP based NWFET, we present current-voltage characteristics and entropy
diagrams for a range of equilibrium and non-equilibrium states. Signatures of
few-electron Coulomb charging effects can be identified, as known from
experimental situations. Furthermore, we illustrate the significance of the
single-particle-reduced entropy by analyzing the corresponding electronic
configurations.
