Transport mechanism in La1.85Sr0.15Cu1-xMgxO4 system

The transport properties of the La1.85Sr0.15Cu1-xMgxO4 solid solution series have been investigated by means of electric resistivity and thermoelectric power measurements. It exhibits a localized behavior for 0.02≤x≤0.2 samples at low temperature. At this temperature range, the conduction property shows two-dimensional variable range hopping behavior. For samples x≥0.3, the small polaron model can well explain the conduction behavior at high temperature. The small polarons are induced by the coupling between the breathing mode phonon and the hole carriers. At low temperature range, the conduction mechanism deviates from the small polaron model and becomes dominated by hopping like process