Realistic models of paracrystalline silicon - art. no. 235207

We present a procedure for the preparation of physically realistic models o f paracrystalline silicon based on a modification of the bond-switching met hod of Wooten, Winer, and Weaire. The models contain randomly oriented c-Si grains embedded in a disordered matrix. Our technique creates interfaces b etween the crystalline and disordered phases of Si with an extremely low co ncentration of coordination defects. The resulting models possess structura l and vibrational properties comparable with those of good continuous rando m network models of amorphous silicon and display realistic optical propert ies, correctly reproducing the electronic band gap of amorphous silicon. Th e largest of our models also shows the best agreement of any atomistic mode l structure that we tested with fluctuation microscopy experiments, indicat ing that this model has a degree of medium-range order closest to that of t he real material.