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Ab initio (first-principles) Molecular-Dynamics Simulation |
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The first-principles molecular-dynamics (FPMD) simulation is an effective method of analyzing physical phenomena on the atomic and electronic levels. Without employing experimental parameters, one can implement the highly accurate simulation based on quantum dynamics by preparing the initial atomic configuration and the number of electrons in the simulation models. This method is indispensable in the development of atomistic production techniques, which require accurate analyses on the atomic and electronic levels. By examining the machining and deposition processes and/or by obtaining efficient information using the FPMD, one can interpret phenomena playing important roles in processes and develop new practical processes.
The figure below shows an example of the FPMD simulation in which surface silicon atoms are etched during the EEM process. The surface atom is removed during the chemical reaction between the SiO2 particle and the surface atom. We can examine the microscopic physical phenomena, which are not easily observed by high-grade microscopy, on a computer display by FPMD simulation. |
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| In this project, not only simulations to explore and predict physical phenomena but also the development of new simulation programs are implemented. For example, the newly developed computational scheme, real-space finite-difference approach, enables us to carry out simulations under external electric fields, which are difficult to treat by conventional FPMD programs. The figure below depicts the field evaporation process of the tungsten adatom from the W(001) surface. The electrons around the adatom are removed due to the external electric field, and then the adatom evaporates from the surface as a positive ion. |
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| Thus, by developing new computational programs and implementing simulations with the developed program, we can improve the experimental conditions in the machining and deposition processes, evaluate the functionalities of nanoscale structures, and develop innovative process techniques using newly discovered physical phenomena. |
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