Nearly constant electrical resistance over large temperature range in Cu3 NMx(M = Cu, Ag, Au) compounds

Abstract

Electrical resistance is a material property that usually varies enormously with temperature. Constant electrical resistivity over large temperature range has been rarely measured in a single solid. Here we report the growth of Cu 3 NM x (M = Cu, Ag, Au) compound films by magnetron sputtering, aiming at obtaining single solids of nearly constant electrical resistance in some temperature ranges. The increasing interstitial doping of cubic Cu 3 N lattice by extra metal atoms induces the semiconductor-to-metal transition in all the three systems. Nearly constant electrical resistance over 200âK..K, from room temperature downward, was measured in some semimetallic Cu 3 NM x samples, resulting from opposite temperature dependence of carrier density and carrier mobility, as revealed by Hall measurement. Cu 3 NAg x samples have the best performance with regard to the range of both temperature and doping level wherein a nearly constant electrical resistance can be realized. This work can inspire the search of other materials of such a quality.