DFT‐Based Insights Into Elastic, Thermophysical, Electronic, and Optical Properties of Topological Insulators XTe ₅ (X = Zr, Hf)

Transition metal penta‐tellurides, ZrTe 5 and HfTe 5 have recently drawn a lot of attention due to their fascinating physical properties and for being prominent materials showing topological phase transitions. In this work, we present first in‐depth investigation of elasto‐mechanical, thermophysical, and optical properties of these compounds. In particular, we analyzed the directional dependence of the elastic properties, explored the optical response for different photon polarization directions and examined previously unreported potential industrial applications of these materials. We also studied their electronic and topological properties. We used Density Functional Theory (DFT) based calculations to study all of these properties. This study suggests that the materials are mechanically stable, possess high mechanical and bondinganisotropy, are soft and brittle in nature. Investigation of thermophysical properties indicates weak bonding strength in these compounds and suggests their possible application in acoustic and thermoelectric devices. Examination of their optical characteristics reveals that they have high refractive indices at low energy. They are very good ultraviolate absorbers and potential candidates for solar coating devices. Our study also reveals that these materials show characteristics of weak ℤ 2 topological insulators. Spin‐orbit interaction is responsible for enhancing energy gaps and promoting insulating characteristics in these compounds.