For 10 points, name this state of matter exemplified by ice.
This phase names a theory describing materials which may have a Fermi level which lies in a gap of the available energy levels for its electrons, and that theory explains how overcoming a small gap may be aided by doping. That theory, the band theory of this phase, is derived from the "nearly free electron" model for this phase, which expands on the simpler "free electron" model. A mixture of compounds assumes this phase below the eutectic point, and a gas transitions to this phase via deposition, the opposite of sublimation. For 10 points, name this state of matter exemplified by ice.
This phase names a theory describing materials which may have a Fermi level which lies in a gap of the available energy levels for its electrons, and that theory explains how overcoming a small gap may be aided by doping.
{Solid}