Amorphous ZrO2 from Ab-initio molecular dynamics: Structural, electronic and dielectric properties

TL;DR

This paper models amorphous ZrO2 using ab-initio molecular dynamics, analyzing its structural, vibrational, electronic, and dielectric properties, revealing similarities to crystalline phases and potential for improved dielectric applications.

Contribution

It introduces a melt-and-quench ab-initio simulation approach to accurately model amorphous ZrO2 and investigates its properties from first principles.

Findings

Total static dielectric constant around 22

Electronic dielectric constant similar to crystalline phases

Structural analysis shows coordination statistics of amorphous ZrO2

Abstract

Realistic models of amorphous ZrO2 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 about 22, comparable to that of the monoclinic phase. This work is motivated by the search for improved gate dielectric materials for sub-0.1 micron CMOS technology, and may also have implications for HfO2 and for silicates of ZrO2 and HfO2.