  Polymer nanocomposite dielectrics are promising materials for electrical
insulation in high voltage applications. However, the physics behind their
performance is not yet fully understood. We use density functional theory to
investigate electronic properties of the interfacial area in magnesium
oxide-polyethylene nanocomposite. Our results demonstrate polyethylene
conduction band matching with conduction bands of different surfaces of
magnesium oxide. Such band bending results in long range potential wells of up
to 2.6 eV deep. Furthermore, the fundamental influence of silicon treatment on
magnesium oxide surface properties is assessed. We report a reduction of the
surface-induced states at the silicon-treated interface. The simulations
provide information used to propose a new model for charge trapping in
nanocomposite dielectrics.
