High Pressure Investigation of the Layered Compound Sr₂Cu₂CoO₂ (S_1-xSe_x) ₂

抄録

The electrical properties of the layered transition metal oxychalcogenides Sr₂Cu₂CoO₂ (S_1-xSe_x) ₂ are investigated at ambient and high pressure. Increasing selenium content results in a lattice expansion and a crossover from low dimensional variable range hopping conduction to a power law dependence of resistivity at low temperatures. The application of high pressure drives the system into the insulating region. The effects are discussed in terms of a charge carrier compensation due to cobalt d-states close to the Fermi energy.