Evolution of concomitant pseudogap formation with the β−to−β′ structural phase transition in melt-quenched As₂Te₃ upon chemical doping.

The chalcogenides are a family of layered compounds that have been utilized in a wide range of applications, and have been shown to exhibit exotic states such as superconductivity, charge density waves, and topological insulation. 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 Bi₂Te₃, a superconducting, topological insulator[2]. A large resistivity anomaly is observed upon cooling from β-As₂Te₃ into the low temperature β' phase.

We have measured the temperature dependent infrared reflectivity of melt-quenched As₂Te₃ and have observed the formation of a pseudogap concomitant to the β to β' phase transition. The results of this experiment along with supplementary resistivity and magnetization measurements suggest the phase transition could be due to the potential formation of a charge density wave. The evolution of this phase transition as dopants such as Cu and Ge are added will be explored.

References

[1] Morin et al. Inorg. Chem 54(20):9936, 2015.

[2] Matsubayashi, et al. PRB, 90:125126, 2014.

[3] Dion et al. PRB 106:075104, 2022.