Multimillion-Atom Simulations of Atomic-Level Surface Stresses and Pressure Distribution on InAs/GaAs Mesas

1999 ◽  
Vol 584 ◽  
Author(s):  
Xiaotao Su ◽  
Rajiv K. Kalia ◽  
Anupam Madhukar ◽  
Aiichiro Nakano ◽  
Priya Vashishta

AbstractLarge-scale molecular dynamics simulations are performed to investigate the atomiclevel stresses on InAs/GaAs mesas. The simulations are based on an interatomic-potential scheme for InAs/GaAs systems which depends on the local chemical composition. Multiresolution techniques are used to speed up the simulations. InAs/GaAs square mesas with { 101 }-type sidewalls are studied. The atomic-level pressure distribution and surface atomic stresses on the sidewalls with 12, 10, 8 and 6 monolayers of InAs overlayers have been calculated.

Author(s):  
S. H. Mahboobi ◽  
A. Meghdari ◽  
N. Jalili ◽  
F. Amiri

One of the key factors in the assembly of nanoclusters is the precise positioning of them by a manipulation system. Currently the size of clusters used as building blocks is shrinking down to a few nanometers. In such cases, the particle nature of matter plays an important role in the manipulator/cluster/substrate interactions. Having a deeper insight to the aforementioned nanoscale interactions is crucial for prediction and understanding of the behavior of nanoclusters during the positioning process. In the present research, 2D molecular dynamics simulations have been used to investigate such behaviors. Performing planar simulations can provide a fairly acceptable qualitative tool for our purpose while the computation time is greatly reduced in comparison to 3D simulations. The system consists of a tip, cluster and substrate. The focus of the present research is on ultra-fine metallic nanoclusters. To perform this research, Nose-Hoover dynamics and Sutton-Chen interatomic potential will be used to investigate the behavior of the above system which is made from different transition metals. The effects of material type, tip form and manipulation strategy on the success of the process have been investigated by planar molecular dynamics. Such qualitative simulation studies can evaluate the chance of success of a certain nanopositioning scenario regarding different working conditions before consuming large-scale computation time or high experimental expenses.


Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4326
Author(s):  
Pawel Goj ◽  
Aleksandra Wajda ◽  
Pawel Stoch

Iron-phosphate glasses, due to their properties, have many potential applications. One of the most promising seems to be nuclear waste immobilization. Radioactive 90Sr isotope is the main short-lived product of fission and, due to its high solubility, it can enter groundwater and pose a threat to the environment. On the other hand, Sr is an important element in hard tissue metabolic processes, and phosphate glasses containing Sr are considered bioactive. This study investigated the effect of SrO addition on a glass structure of nominal 30Fe2O3-70P2O5 chemical composition using classical molecular dynamics simulations. To describe the interaction between Sr-O ion pairs, new interatomic potential parameters of the Buckingham-type were developed and tested for crystalline compounds. The short-range structure of the simulated glasses is presented and is in agreement with previous experimental and theoretical studies. The simulations showed that an increase in SrO content in the glass led to phosphate network depolymerization. Analysis demonstrated that the non-network oxygen did not take part in the phosphate network depolymerization. Furthermore, strontium aggregation in the glass structure was observed to lead to the non-homogeneity of the glass network. It was demonstrated that Sr ions prefer to locate near to Fe(II), which may induce crystallization of strontium phosphates with divalent iron.


2016 ◽  
Vol 34 (4) ◽  
pp. 041509 ◽  
Author(s):  
Daniel Edström ◽  
Davide G. Sangiovanni ◽  
Lars Hultman ◽  
Ivan Petrov ◽  
J. E. Greene ◽  
...  

Nano Letters ◽  
2017 ◽  
Vol 17 (10) ◽  
pp. 5919-5924 ◽  
Author(s):  
Zheyong Fan ◽  
Petri Hirvonen ◽  
Luiz Felipe C. Pereira ◽  
Mikko M. Ervasti ◽  
Ken R. Elder ◽  
...  

2017 ◽  
pp. 141-177 ◽  
Author(s):  
Stefan J. Eder ◽  
Ulrike Cihak-Bayr ◽  
Davide Bianchi

Sign in / Sign up

Export Citation Format

Share Document