How Ice enables Superconductivity in Na_xCoO_2.yH_2O by melting charge order: Possibility of novel Electric Field Effects

Charge ordering in doped \cob planes near the commensurate fillings $x = {1/4}$and1\mathrm{/}3areconsideredfor$Na_x CoO_2.yH_2O$ and suggested to be competitors to superconductivity, leading to the experimentally seen narrow superconducting dome bounded by commensurate doping: $1\mathrm{/}4<x<1\mathrm{/}3$. Intercalated hydrogen bonded $H_{2}O$ network, by its enhanced dielectric constant, screen and frustrate local {\em charge order condensation energy} and replace a generic charge glass order' by superconductivity in the dome. An access to superconductivity and charge order, available through the new water channel, is used to predict novel effects such as Electrical Modulation of Superconductivity’ and `Electroresistance Effect’.