Dresden 2017 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 44: Postersession II
DS 44.4: Poster
Donnerstag, 23. März 2017, 17:00–19:00, P1C
Tuning excitons by 3D stacking of hexagonal boron nitride layers — •Wahib Aggoune1,2, Caterina Cocchi2, Dmitrii Nabok2, Karim Rezouali1, Mohamed Akli Belkhir1, and Claudia Draxl2 — 1Laboratoire de Physique Théorique, Faculté des sciences exactes, Université de Bejaia, 06000 Bejaia, Algérie — 2Institut für Physik and IRIS Adlershof, Humboldt-Universität zu Berlin, Berlin, Germany
The opto-electronic properties of hexagonal boron-nitride (h-BN) are investigated from first principles, considering the five possible stacking arrangements obtained by translation of the two layers in the unit cell. We find the most stable structure in agreement with experiment [1] and with an earlier first-principles study [2]. All structures exhibit a quasi-particle gap, with values between 4.5 and 6 eV as calculated from the G0W0 approach. From the solution of the two-particle Bethe-Salpeter equation an intense excitonic peak is found in the UV region for any stacking arrangement. Depending on the order of the h-BN layers, the lowest-energy excitation can be either bright or dark. We characterize the main optical excitations for all stacking arrangements and discuss them in the context of symmetry-induced selection rules. All calculations are performed using the exciting code [3], a full-potential all-electron package implementing the families of linearized augmented planewave methods.
[1] R. S. Pease, Nature (London) 165, 722 (1950). [2] L. Liu et al., Phys. Rev. B 68, 104102 (2003). [3] A. Gulans et al., J. Phys. Condens. Matter. 26, 363202 (2014).