First-principles studies on mechanical properties and band structures of TMO2 (TM = Zr or Hf) nanostructures under high pressure

The mechanical and band structure studies of TMO2 (TM = Zr or Hf) nanostructures under high pressure in the range of 0 GPa and 50 GPa is studied using density functional theory. Upon applying the pressure, the unit cell size decreases for TMO2 nanostructures. The Young's and bulk modulii of TMO2 decreases until 30 GPa and then increases up to 50 GPa. The universal anisotropy increases with the increase in the pressure. The ZrO2 and HfO2 nanostructure turns from ductile to brittle nature for the applied pressure beyond 30 GPa, which is inferred from Pugh's criterion. The band gap of TMO2 increases with the increase in the applied pressure. The findings show the various transformations of TMO2 nanostructures under high pressure, which can be used for tailoring the band gap and mechanical properties of TMO2 nanomaterials.