HPC++ Europe: Optical Properties of BN Nanotubes and Hexagonal BN


Status: finished project
Starting date 
1 May 2008
Ending date 
31 May 2008

In this project, we plan to calculate electronic excitations in BN nanotubes with ab-initio techniques. In particular, we would like to study the role of the defects on the optical properties of these nanostructures.  In fact, recently in view of UV-lasing, the luminescence of hexagonal boron nitride (BN) structure has been measured  [K. Watanabe, T. Taniguchi, and H. Kanda, Nature Mat. 3, 404, (2004),  M. G. Silly, P. Jaffrennou, J. Barjon, J.-S. Lauret,  F. Ducastelle, A. Loiseau, E. Obraztsova, B. Attal-Tretout,   and E. Rosencher Phys. Rev.  B 75, 085205 (2007)], but the interpretation of  the experimental results is still cumbersome. The obtained emission spectra is  more than 2eV below the predicted theoretical band gap [L. Wirtz, A. Marini, and A. Rubio, Phys. Rev. Lett. 96, 126104 (2006)].  It is not possible to explain these results as due to the band structure of hexgonal-BN or to correlation effects, and this is the reason that motived us to investigate the role of defects in luminescence spectra. The project involves the use of existing computer codes that implements the techniques of many-body perturbation theory in plane waves (Yambo).