GROUND-STATE OF GRANULAR METALS

We argue that for granular metals a sizable fraction of the grains bec omes charged because the energy fluctuation of the highest-occupied le vel of each grain, as predicted by random matrix theory, is larger tha n the charging energy. We have computed the ground state density of st ates and the degree of ionization of granular metals. The density of s tates shows a Coulomb gap around the Fermi energy, produced by the lon g-range part of the Coulomb interactions, which should dominate transp ort properties at low temperatures.