  We analyse the effects of applying an electric field on the critical
temperature, Ts, at which superionicity appears in archetypal fast ion
conductor CaF2 by means of molecular dynamics simulations. We find that the
onset of superionicity can be reduced by about 100K when relatively small
electric fields of ~50KV/cm are employed. Under large enough electric fields,
however, ionic conductivity is depleted. The normal to superionic phase
transition is characterised by a large increase of entropy, thereby sizeable
electrocaloric effects can be realised in fast ion conductors that are
promising for solid-state cooling applications.
