Exploring Dielectric Properties in Atomistic Models of Amorphous Boron Nitride

We report a theoretical study of dielectric properties of models of amorphousBoron Nitride, using interatomic potentials generated by machine learning. Wefirst perform first-principles simulations on small (about 100 atoms in theperiodic cell) sample sizes to explore the emergence of mid-gap states and itscorrelation with structural features. Next, by using a simplified tight-bindingelectronic model, we analyse the dielectric functions for complex threedimensional models (containing about 10.000 atoms) embedding varyingconcentrations of sp^1, sp^2 and sp^3 bonds between B and Natoms. Within the limits of these methodologies, the resulting value of thezero-frequency dielectric constant is shown to be influenced by the populationdensity of such mid-gap states and their localization characteristics. Weobserve nontrivial correlations between the structure-induced electronicfluctuations and the resulting dielectric constant values. Our findings arehowever just a first step in the quest of accessing fully accurate dielectricproperties of as-grown amorphous BN of relevance for interconnect technologiesand beyond.