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Current Research > Computational
materials science |
Using quantum mechanical and analytic potentials, we simulate the formation and properties of advanced materials for new applications in the fields of microelectronics, nanotechnology, and biomedical science. Diamond-like Carbon Tetrahedral amorphous carbon (ta-C) is a diamond-like form of carbon with applications in blades, wear-resistant coatings and protective barriers. Our simulations were the first to model thin-film deposition of ta-C, and showed that the growth mechanism was not as expected. Quantum Computing In collaboration with the Centre for Quantum Computer Technology we are working on simulating aspects of the fabrication process of their design for a solid-state nuclear-spin quantum computer. This design requires precise positioning of individual phosphorus atoms in a pure silicon matrix. Low-flux ion implantation in conjunction with electron beam lithography is one of the proposed technologies to build the device. We have performed large numbers of simulations of implantation of ions in the 1 keV range using the EDIP empirical potential for silicon. The calculations show that for the implantation to have sufficiently high yields it may be necessary to implant down the crystallographic axes. In more recent work we have used ab initio Car-Parrinello techniques to investigate the structure and electronic density of phosphorus dopant structures laid on top of the silicon surface. We hope to provide data to aid in the identification and characterisation of surface phosphorus complexes using scanning tunneling microscopy. Giant-Magneto-Resistance Giant-Magnetio-Resistance is the core technology in disk drives, and employs alternating layers of metallic material only a few atomic planes in thickness. It is not known why the inexpensive sputtering method produces better films than the expensive Molecular Beam Epitaxy. Our simulations were the first to model the sputtering deposition procedures. Shown here is a Co thin film (atoms in red) deposited onto a Cu substrate (atoms in green) with a grain boundary. Wannier Function Analysis Hydrogenated amorphosu silicon carbide (a-SiC:H) is a variable band gap material with important electronic and optical applications. To better understand this material we have generated A-SiC:H structures with varying density and stochiometry using Car-Parrinello molecular dynamics. To analyse the complex bonding in a-SiC:H we are using the new technique of maximally localised Wannier functions. Shown here is a small fragment with hydogen, carbon and silicon shown as blue, red and green. The small black circles indicate the Wannier centres, and identify single and double bonds, and an intruiging three-atom bond. People
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