Exploring dielectric properties in atomistic models of amorphous boron nitride

T Galvani and AK Hamze and L Caputo and O Kaya and SMM Dubois and L Colombo and VH Nguyen and Y Shin and HJ Shin and JC Charlier and S Roche, JOURNAL OF PHYSICS-MATERIALS, 7, 035003 (2024).

DOI: 10.1088/2515-7639/ad4c06

We report a theoretical study of dielectric properties of models of amorphous Boron Nitride, using interatomic potentials generated by machine learning. We first perform first-principles simulations on small (about 100 atoms in the periodic cell) sample sizes to explore the emergence of mid-gap states and its correlation with structural features. Next, by using a simplified tight-binding electronic model, we analyse the dielectric functions for complex three dimensional models (containing about 10.000 atoms) embedding varying concentrations of sp1, sp2 and sp3 bonds between B and N atoms. Within the limits of these methodologies, the resulting value of the zero-frequency dielectric constant is shown to be influenced by the population density of such mid-gap states and their localization characteristics. We observe nontrivial correlations between the structure-induced electronic fluctuations and the resulting dielectric constant values. Our findings are however just a first step in the quest of accessing fully accurate dielectric properties of as-grown amorphous BN of relevance for interconnect technologies and beyond.

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