Metallization of Nanofilms in Strong Adiabatic Electric Fields

We introduce an effect of metallization of dielectric nanofilms by strong, adiabatically varying electric fields. The metallization causes optical properties of a dielectric film to become similar to those of a plasmonic metal (strong absorption and negative permittivity at low optical frequencies). This is a quantum effect, which is exponentially size-dependent, occurring at fields on the order of 0.1 V/ and pulse durations ranging from ~1 fs to ~10 ns for a film thickness of 3--10 nm.