Lattice dynamics in the conformational environment of multilayered hexagonal boron nitride (h-BN) conveys to peculiar infrared optical responses

Abstract

We report a detailed study of the stability and dynamical lattice properties of five possible differently stacked configurations of bulk hexagonal boron nitride (h-BN). The results are obtained upon comparison among different theoretical methods, namely Local Density Approximation (LDA) and Generalized Gradient Approximation (GGA) Density Functional Theory (DFT) approaches. We devote particular attention to the prominent role played by the pseudopotential approximation in the theoretical framework and differently from previous implementations, we obtain the best performances from GGA rather than LDA. The major complication, nevertheless, consists in the necessity of a complex approach for the non-analytical part of the dynamical matrix. Our conclusions are based on the agreement of the calculated data with a set of infrared spectroscopy measurements, taken from the experimental literature. Besides, we apply the theoretical model to derive, from geometrical considerations, an empirical method for the calculation of the non-analytical part of the dynamical matrix for potential use in discerning techniques.