Variable range hopping conductivity in reduced lead glass

Abstract

We have measured the conductivity of a sample of reduced channel-plate lead glass over the temperature range 25–300 K. The behavior is consistent with conduction by two-dimensional variable range hopping. From measurements of the thickness of the conducting layer we estimate the wave-function overlap parameter α−1⩾50 Å and hence from the temperature dependence of the conduction we deduce that the density of states at the Fermi level is less than 4×1017 eV−1 cm−3.