Structural, electronic, and dielectric properties of amorphousZrO2fromab initiomolecular dynamics

Abstract

Realistic models of amorphous $\mathrm{Zr}{\mathrm{O}}_2$ are generated in a “melt-and-quench” fashion using ab initio molecular dynamics in a plane-wave pseudopotential formulation of density-functional theory. The structural properties of the resulting amorphous models are analyzed, with special attention to coordination statistics. The vibrational and dielectric properties of one of these models are then investigated from first principles using linear-response methods. The electronic dielectric constant and Born effective charges are found to be very similar to those of the crystalline phases. Encouragingly, the predicted total static dielectric constant is $\sim 22$, comparable to that of the monoclinic phase. This work is motivated by the search for improved gate dielectric materials for sub-$0.1\text{−}\mu \mathrm{m}$ complementary metal oxide semiconductor technology, and may also have implications for $\mathrm{Hf}{\mathrm{O}}_2$ and for silicates of $\mathrm{Zr}{\mathrm{O}}_2$ and $\mathrm{Hf}{\mathrm{O}}_2$.