Dear All, I have performed calculations for two double perovskite oxide materials and the band gap of the material is found to be more than 1. 3 eV for both materials. The calculations have been performed using GGA+U, since it contains rare earth materials. The value of U have been used from the literature. The energy convergence was performed till 0.0001 Ry and the optical properties were calculated using optic. However, the imaginary part of the dielectric constant (epsilon 2) shows non-negligible value below the energy band gap. PBE was used as the exchange correlation functional and if I am not wrong then for the calculation of epsilon 2 the contribution of inter-band transitions are taken into consideration and the intra-bands are neglected. Then what is the reason for the non-zero value of epsilon 2 below the energy band gap? If anyone could suggest some views, I would be very grateful. Please let me know, if anyone needs more information.
Sincerely, Anup Pradhan Sakhya, TIFR.
_______________________________________________ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
