ABINIT is a package whose main program allows one to find the total energy, charge density, electronic structure and many other properties of systems made of electrons and nuclei, (molecules and periodic solids) within Density Functional Theory (DFT), Many-Body Perturbation Theory (GW approximation and Bethe-Salpeter equation) and Dynmical Mean Field Theory (DMFT). ABINIT also allows to optimize the geometry according to the DFT forces and stresses, to perform molecular dynamics simulations using these forces, and to generate dynamical matrices, Born effective charges and dielectric tensors. The present paper aims to describe the new capabilities of ABINIT that have been developed since 2009. It covers both physical and technical developments inside the ABINIT code, as well as developments provided within the ABINIT package. The developments are described with relevant references, input variables, tests and tutorials.

Carefully converged calculations are performed for the band gap of ZnO within many-body perturbation theory (G 0 W 0 approximation). The results obtained using four different well-established plasmon-pole models are compared with those of explicit calculations without such models (the contour-deformation approach). This comparison shows that, surprisingly, plasmon-pole models depending on the f -sum rule gives less precise results. In particular, it confirms that the band gap of ZnO is underestimated in the G 0 W 0 approach as compared to experiment, contrary to the recent claim of Shih et al.

Phone: þ32 10 479359, Fax: þ32 10 473452We review some recent developments in many-body perturbation theory (MBPT) calculations that have enabled the study of interfaces and defects. Starting from the theoretical basis of MBPT, Hedin's equations are presented, leading to the GW and GWG approximations. We introduce the perturbative approach, that is the one most commonly used for obtaining quasiparticle (QP) energies. The practical strategy presented for dealing with the frequency dependence of the self-energy operator is based on either plasmon-pole models (PPM) or the contour deformation technique, with the latter being more accurate. We also discuss the extrapolar method for reducing the number of unoccupied states which need to be included explicitly in the calculations. The use of the PAW method in the framework of MBPT is also described. Finally, results which have been obtained using MBPT for band offsets at interfaces and for defects are presented, with emphasis on the main difficulties and caveats.Schematic representation of the QP corrections (marked with d) to the band edges (E v and E c ) and a defect level (E d ) for a Si/ SiO 2 interface (Si and O atoms are represented in blue and red, respectively, in the ball-and-stick model) with an oxygen vacancy leading to a Si-Si bond (the Si atoms involved in this bond are colored light blue).