Optimal atomic structure of amorphous silicon obtained from density functional theory calculations

Atomic structure of amorphous silicon consistent with several reported experimental measurements has been obtained from annealing simulations using electron density functional theory calculations and a systematic removal of weakly bound atoms. The excess energy and density with respect to the crystal are well reproduced in addition to radial distribution function, angular distribution functions, and vibrational density of states. No atom in the optimal configuration is locally in a crystalline environment as deduced by ring analysis and common neighbor analysis, but coordination defects are present at a level of 1%–2%. The simulated samples provide structural models of this archetypal disordered covalent material without preconceived notion of the atomic ordering or fitting to experimental data.We thank G Barkema for fruitful discussions and for providing us with the CRN sample. The Poitou-Charentes Region is gratefully acknowledged for supporting a three month stay of A Pedersen in France. Financial support was also provided by the Icelandic Research Fund. The computations were carried out using the Nordic High Performance Computing (NHPC) facility in Iceland.Peer Reviewe