Large and Realistic Models of Amorphous Silicon
Physics and Astronomy
Amorphous silicon (a-Si) models are analyzed for structural, electronic and vibrational characteristics. Several models of various sizes have been computationally fabricated for this analysis. It is shown that a recently developed structural modeling algorithm known as force-enhanced atomic refinement (FEAR) provides results in agreement with experimental neutron and X-ray diffraction data while producing a total energy below conventional schemes. We also show that a large model (∼ 500 atoms) and a complete basis is necessary to properly describe vibrational and thermal properties. We compute the density for a-Si, and compare with experimental results.
Color code: green (four-fold coordinated), salmon (over/under coordinated).
Figure: (Top panel, left): A random configuration of 512 silicon atoms in a supercell. (Top panel, right): Same random coordinates after inversion with FEAR. (Bottom panel): Comparison of structural and vibrational properties for different FEAR models with experimental results.
Journal of Non-Crystalline Solids
Drabold, D. A.
(2018). Large and Realistic Models of Amorphous Silicon. Journal of Non-Crystalline Solids, 492, 27-32.
Available at: https://aquila.usm.edu/fac_pubs/15101