Effect of Copper Doping on the Polymorphic Chalcogenide As₂Te₃

The chalcogenides are a family of layered compounds that have been exploited in a wide range of applications such as phase change memory, photodetectors, and thermoelectric cooling. As₂Te₃ is a layered semiconducting material with three different allotropic phases, α, β and β′[1]. β-As₂Te₃ is of interest as it is isostructural to Bi₂Te_3, a superconducting, topological insulator, that has been a topic of much research over the past decade[2]. β-As₂Te₃ is predicted to be a topological insulator at high pressure[3].

We have doped β-As₂Te₃ with copper and investigated the changes in the optical, electronic, and thermodynamic properties. Characterization via differential scanning calorimetry (DSC), infrared reflectivity, Raman scattering as well as X-Ray diffraction will be discussed as a function of copper doping in β-As₂Te₃. The focus will be on the optical properties, as well as evidence of a new high temperature phase transition found with DSC.

References
[1] C. Morin et al. Inorg. Chem 54(20):9936–9947,2015. PMID: 26418840.
[2] K. Matsubayashi, et al. Phys. Rev. B, 90:125126, Sep 2014.
[3] Koushik Pal et al. Applied Physics Letters, 105(6):062105, 2014.