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CPP 99: Frontiers in Electronic-Structure Theory - Focus on Electron-Phonon Interactions V (joint session O/CPP/DS/HL)
CPP 99.3: Vortrag
Donnerstag, 19. März 2020, 15:45–16:00, GER 38
Understanding the lattice dynamics of 3D hexagonal boron nitride (h-BN): beyond the LDA approach — •Luigi Cigarini, Michal Novotný, and František Karlický — Department of Physics, Faculty of Science, University of Ostrava, Czech Republic
It is fundamental to achieve a clear depiction of the lattice dynamics of 3D h-BN in order to understand the experimental outcomes. Five different stacking conformations are possible for 3D h-BN and at least two or three of them are systematically present in samples in variable amounts [1-2], resulting as a source of irreproducibility for experiments, such as the infrared optical response [3-4].
The lattice dynamics of h-BN is particularly tough to describe, stated the different nature of the forces participating in it: covalent bonds and Van der Waals interactions. The LDA approach seemed to be the most effective compromise, at the DFT level [1,5-6].
In this work we explain the surprisingly good performance of LDA. We also show that it is possible to achieve better results, in comparison with experimental IR spectra, by using, instead, the GGA approach to DFT and treating separately the two parts of the dynamical matrix. Besides, we found that IR spectroscopy is able to give some information about stacking composition. . Liu, L. et al., Phys. Rev. B, 68(10), 104102 (2003). . Constantinescu, G. et al., Phys. Rev. Lett., 111(3), 036104 (2013). . Çamurlu, H.E. et al., Ceram. Int., 42(5), 6312-6318 (2016). . Mukheem, A. et al., Nanomaterials, 9(4), 645 (2019). . Cuscó, R. et al., Phys. Rev. B, 97(15), 155435 (2018). . Serrano, J. et al., Phys. rev. lett., 98(9), 095503 (2007).