Metallic Binary Copper Chalcogenides with Orthorhombic Layered Structure

Abstract

Chalcogenide materials have regained attention after the recent recognition of the compatibility of transition metal dichalcogenides with graphene. Additionally, there has been a recent appreciation for the rich variety of properties they support due to the anomalies in the materials’ intrinsic band structure. These materials generally have layered structures and weak interlayer connection through the chalcogen layer and its van der Waals type bonding. We have synthesized orthorhombic copper telluride and measured its electrical transport properties. The results of these measurements reveal that the conduction is metallic in both the in-plane and out-of-plane directions. The range of stability of this structure is examined along with the lattice constants. The independence of the resistivity in samples to changes in excess copper indicates that the transport is essentially within the conducting planes. This result shows that the material hosts two-dimensional character likely due to its covalent interlayer bonding.

Improved ZT in ball‐milled and spark plasma sintered Cu15As30Te55 glass‐ceramics

“…7,24 An effect of the numerous interfaces created by the fine microstructure (~200 nm) on the phonon transport cannot as well be excluded to explain this trend. Note that (a) the variability for t BM = 0 minute can probably be related to the extremely variable remaining glass fraction for these samples (Figure 9); (b) the fact that the thermal conductivity reaches 1.8 W/m/K, while the thermal conductivity of the Cu 15 As 30 Te 55 parent glass is about 0.22 W/m/K, or that of the α or β-As 2 Te 3 crystalline phase does not exceed 1.0 W/ m/K 24 and 1.4 W/m/K, respectively 7 , could be explained by the presence of additional metallic phases, viz., the Cu 1.4 Te rickardite 25 and AsTe. 22 On the other hand, the resistivity values are subjected to a larger sample-to-sample variability, which probably masks the evolution of this property.…”