Electron transport and magnetic properties of some mixed-valent alkalithiocuprates

Abstract

Electrical transport properties of some two-dimensional isostructural compounds KCu₄S₃, RbCu₄S₃, and CsCu₄S₃ and a one dimensional conductor Na₃Cu₄S₄ have been investigated. Conductivities have been measured on pelletized materials in the temperature range 300 to 150 K. All of them behave as metallic conductors. The room temperature conductivities of these compounds are KCu₄S₃, 1600 Ω^-1 cm^-1; RbCu₄S₃, 1400 Ω^-1 cm^-1; CsCu₄S₃, 1250 Ω^-1 cm^-1; Na₃Cu₄S₄, 700 Ω^-1 cm^-1. The observed trend in conductivities among the isostructural compounds may be rationalized either on the basis of shortest Cu---Cu distances or on the carrier charge concentrations per unit volume. All of these compounds behave as Pauli paramagnetic materials.