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Title: A genetic algorithm approach in interface and surface structure optimization

The thesis is divided into two parts. In the first part a global optimization method is developed for the interface and surface structures optimization. Two prototype systems are chosen to be studied. One is Si[001] symmetric tilted grain boundaries and the other is Ag/Au induced Si(111) surface. It is found that Genetic Algorithm is very efficient in finding lowest energy structures in both cases. Not only existing structures in the experiments can be reproduced, but also many new structures can be predicted using Genetic Algorithm. Thus it is shown that Genetic Algorithm is a extremely powerful tool for the material structures predictions. The second part of the thesis is devoted to the explanation of an experimental observation of thermal radiation from three-dimensional tungsten photonic crystal structures. The experimental results seems astounding and confusing, yet the theoretical models in the paper revealed the physics insight behind the phenomena and can well reproduced the experimental results.
Authors:
 [1]
  1. Iowa State Univ., Ames, IA (United States)
Publication Date:
OSTI Identifier:
985315
Report Number(s):
IS--T 3007
TRN: US201016%%2182
DOE Contract Number:
AC02-07CH11358
Resource Type:
Thesis/Dissertation
Research Org:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALGORITHMS; CRYSTAL STRUCTURE; GENETICS; GRAIN BOUNDARIES; OPTIMIZATION; PHYSICS; THERMAL RADIATION; TUNGSTEN