Relaxed continuous random network models

1974 ◽  
Vol 15 (2) ◽  
pp. 199-214 ◽  
Author(s):  
P Steinhardt ◽  
R Alben ◽  
D Weaire
2018 ◽  
Vol 51 (6) ◽  
pp. 1544-1550
Author(s):  
Aly Rahemtulla ◽  
Bruno Tomberli ◽  
Stefan Kycia

The atomic arrangements in amorphous solids, unlike those in crystalline materials, remain elusive. The details of atom ordering are under debate even in simplistic random network models. This work presents further advancements in the local atomic motif (LAM) method, first through the introduction of an optimized alignment procedure providing a clearer image of the angular ordering of atoms in a model. Secondly, by applying stereographic projections with LAMs, the angular ordering within coordination shells can be quantified and investigated. To showcase the new capabilities, the LAM method is applied to amorphous germanium, the archetype of covalent amorphous systems. The method is shown to dissect structural details of amorphous germanium (a-Ge) from the continuous random network (CRN) model and a reverse Monte Carlo (RMC) refined model fitted to high-resolution X-ray scattering measurements. The LAMs reveal well defined dihedral ordering in the second shell. The degree of dihedral ordering is observed to be coupled to bond length distances in the CRN model. This coupling is clearly not present within the RMC refined model. The LAMs reveal inclusions of third-shell atoms occupying interstitial positions in the second shell in both models.


1975 ◽  
Vol 17 (3) ◽  
pp. 299-318 ◽  
Author(s):  
J.F. Graczyk ◽  
P. Chaudhari

1973 ◽  
Vol 8 (12) ◽  
pp. 6021-6023 ◽  
Author(s):  
Paul Steinhardt ◽  
Richard Alben ◽  
M. G. Duffy ◽  
D. E. Polk

2000 ◽  
Vol 276-278 ◽  
pp. 463-464 ◽  
Author(s):  
N Zotov ◽  
F Bellido ◽  
M Dominguez ◽  
A.C Hannon ◽  
R Sonntag

Author(s):  
S. R. Herd ◽  
P. Chaudhari

Electron diffraction and direct transmission have been used extensively to study the local atomic arrangement in amorphous solids and in particular Ge. Nearest neighbor distances had been calculated from E.D. profiles and the results have been interpreted in terms of the microcrystalline or the random network models. Direct transmission electron microscopy appears the most direct and accurate method to resolve this issue since the spacial resolution of the better instruments are of the order of 3Å. In particular the tilted beam interference method is used regularly to show fringes corresponding to 1.5 to 3Å lattice planes in crystals as resolution tests.


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