Atypical Pressure Dependent Structural Phonon and Thermodynamic Characteristics of Zinc Blende BeO

TL;DR

This paper studies the unique structural and thermal properties of zinc blende beryllium oxide under pressure, which could improve high-tech electronics and thermal management.

Contribution

The study reveals atypical pressure-dependent phonon and thermodynamic behaviors in zinc blende BeO due to its unique atomic structure.

Findings

Zinc blende BeO shows unusual Grüneisen parameter and thermal expansion behavior under pressure.

Short bond length and localized electron charge near Be atoms explain the atypical thermal properties.

Rigid-ion model simulations align with limited experimental and first-principle data.

Abstract

Under normal conditions, the novel zinc blende beryllium oxide (zb BeO) exhibits in a metastable crystalline phase, which is less stable than its wurtzite counterpart. Ultrathin zb BeO epifilms have recently gained significant interest to create a wide range of advanced high-resolution, high-frequency, flexible, transparent, nano-electronic and nanophotonic modules. BeO-based ultraviolet photodetectors and biosensors are playing important roles in providing safety and efficiency to nuclear reactors for their optimum operations. In thermal management, BeO epifilms have also been used for many high-tech devices including medical equipment. Phonon characteristics of zb BeO at ambient and high-pressure P ≠ 0 GPa are required in the development of electronics that demand enhanced heat dissipation for improving heat sink performance to lower the operating temperature. Here, we have reported methodical simulations to comprehend P-dependent structural, phonon and thermodynamical properties by using a realistic rigid-ion model (RIM). Unlike zb ZnO, the study of the Grüneisen parameter γ(T) and thermal expansion coefficient α(T) in zb BeO has revealed atypical behavior. Possible reasons for such peculiar trends are attributed to the combined effect of the short bond length and strong localization of electron charge close to the small core size Be atom in BeO. Results of RIM calculations are compared/contrasted against the limited experimental and first-principle data.

Figures