Effect of the surface on the internal structure of CdSe crystal lattice based on molecular dynamics simulations

Effect of interaction of external surfaces on the symmetry and lattice distortion of CdSe nanocrystals by molecular dynamics simulations

“…MD simulations were performed for cylindrical models of 12 nm in diameter. The cylinders were approximately 2.5 nm thick so that the distance between the terminating planes is comparable to the relaxation length of the surface strains previously determined for thick CdSe cylinders (Stelmakh et al 2017 ). In this work, models terminated by the same low-index atomic terminal planes, (100), (110), (111)A, and (111)B, are examined.…”

“…In our recent study performed for CdSe cylinders built from 20 to 26 CdSe layers, the average values of interatomic distances were measured inside individual atomic planes parallel to the surface and also between adjacent atomic planes (Stelmakh et al 2017 ). Possible anisotropy of the lattice deformation was not accounted for and therefore changes of the symmetry were not analyzed.…”

“…We found that, among four different surface types under examination, the end layers of (100) and (111)B surfaces lose the long range ordering and the surface adopts a disordered structure. At the (110) and (111)A surfaces, long-range order and the symmetry are preserved (Stelmakh et al 2017 ). In the present work, we examine anisotropy of changes of the interatomic distances which occurs at the surface and which may affect the symmetry of the internal crystal lattice.…”

“…The effect of interaction of two opposite parallel surfaces was evaluated by comparison to the effects determined previously for 6-nm thick models (Stelmakh et al 2017 ).…”

“…This borderline depth can be called the relaxation length of the surface strain (RL). In crystals with sizes comparable to surface relaxation length the strains appearing at the end surfaces (their magnitude depending on the atomic planes terminating the crystal) will obviously interact with each other, i.e., the changes of positions of atoms underneath the terminating surfaces will overlap (Stelmakh et al 2017 ). This effect can appear in nanocrystals with only a few nanometers in size.…”