Composition Dependent Electronic Conductivity and Hall Coefficient of β‐Ag₂ + ΔS

Abstract

The electronic conductivity, σe, and the Hall coefficient, RH, of β‐Ag2 + δS are experimentally determined at temperatures T between 190°C and 320°C and at values of δ covering the entire stability range. The change of composition is achieved by in situ coulometric titration. At δ > 5 · 10−4, where β‐Ag2 + δS shows a metallic behaviour, the data are consistent with a parabolic conduction band and an electronic relaxation time which is proportional to T−3/2, but does not depend on the electronic energy. The same concept, plus number densities of defect electrons taken from the titration curves, is also used for an interpretation of σe and RH at smaller δ, where the metal‐semiconductor transition is observed.