Eur. Phys. J. B (2015) 88: 305
https://doi.org/10.1140/epjb/e2015-60292-1

Regular Article

Quantum mechanical ab initio calculations of the structural, electronic and optical properties of bulk gold nitrides

¹ National Institute for Theoretical Physics, School of Physics and Mandelstam Institute for Theoretical Physics, University of the Witwatersrand, Johannesburg, Wits 2050, South Africa
² Department of Physics, Sudan University of Science and Technology, Khartoum, Sudan

^a e-mail: suleiman@aims.ac.za

Received: 15 April 2015
Received in final form: 13 September 2015
Published online: 23 November 2015

Abstract

In the present work, the atomic and the electronic structures of Au₃N, AuN and AuN₂ are investigated using first-principles density-functional theory (DFT). We studied cohesive energy vs. volume data for a wide range of possible structures of these nitrides. Obtained data were fitted to a Birch-Murnaghan third-order equation of state (EOS) so as to identify the most likely candidates for the true crystal structure in this subset of the infinite parameter space, and to determine their equilibrium structural parameters. The analysis of the electronic properties was achieved by the calculations of the band structure and the total and partial density of states (DOS). Some possible pressure-induced structural phase transitions have been pointed out. Further, we carried out GW₀ calculations within the random-phase approximation (RPA) to the dielectric tensor to investigate the optical spectra of the experimentally suggested modification: Au₃N(D0₉). Obtained results are compared with experiment and with some available previous calculations.