A Theoretical Investigation on the Physical Properties of Zirconium Trichalcogenides, ZrS₃, ZrSe₃ and ZrTe₃ Monolayers

In a recent advance, zirconium triselenide (ZrSe₃) nanosheets with anisotropic and strain-tunable excitonic response were experimentally fabricated. Motivated by the aforementioned progress, we conduct first-principle calculations to explore the structural, dynamic, Raman response, electronic, single-layer exfoliation energies, and mechanical features of the ZrX₃ (X = S, Se, Te) monolayers. Acquired phonon dispersion relations reveal the dynamical stability of the ZrX₃ (X = S, Se, Te) monolayers. In order to isolate single-layer crystals from bulk counterparts, exfoliation energies of 0.32, 0.37, and 0.4 J/m² are predicted for the isolation of ZrS₃, ZrSe₃, and ZrTe₃ monolayers, which are comparable to those of graphene. ZrS₃ and ZrSe₃ monolayers are found to be indirect gap semiconductors, with HSE06 band gaps of 1.93 and 1.01 eV, whereas the ZrTe₃ monolayer yields a metallic character. It is shown that the ZrX₃ nanosheets are relatively strong, but with highly anisotropic mechanical responses. This work provides a useful vision concerning the critical physical properties of ZrX₃ (X = S, Se, Te) nanosheets.