Prof. Chung Yuan Kung
National Chung Hsing University, China
Title: Two-dimensional atomic site pattern for a four way symmetric tile and their inner structure, and 3-D quasi crystal model
Abstract:
Large Penrose tiles can be easily constructed by using different coupling schemes of six isomorphic decagons, and four-way symmetric two-dimensional tiles can also be made. The main reason for constructing the four-way symmetric tiles, because they are particularly easy for intercepting of unit cells with a particular shapes, especially the rhombuses shape of acute angles of 36 degrees and 72 degrees for matching the observed atom site of HRTEM Photos.
These unit cells can be self-coupled (aligned) to form a new type of (infinite) tiles that are completely different from their parent tiling. These unit cells can also be varied by replacing the internal decagons with different isomorphic decagons, creating several different unit cells of isomorphic style, all of which can be combined to form another new crystal.
We have observed that these isomorphic unit cells can be aligned periodically, and can be applied to explain atomic position of several HRTEM structures, which may be called as isomorphic periodic Crystal.
We have successfully to compare the Penrose tile to the atom array of HRTEM, and made 3-D models for both Penrose tile and 3-D quasi crystal.
Biography:
Dr. Kung graduated from National Tsing Hua University 1969 and 1972 with BS and MS degree in physics, university of Alabama in Huntsville 1974 in physics and Northwestern university 1979 in material science. Post doctor at Georgia Tech and research science at Lawrence laboratory. With about 6 years experiences in US industries Fairchild and National Semiconductor and work for ITRI (Taiwan) since 1987 and worked for National Chung-Hsing University electric engineering department since 1991 to 2016 (retired).