Harnessing petascale computing to elucidate fundamental mechanisms driving nanopatterning of multicomponent surfaces by directed irradiation synthesis

Jean Paul Allain, University of Illinois at Urbana-Champaign

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Directed irradiation synthesis of nanostructures on compound surfaces has tremendous potential as a method for rationally designing advanced nanomaterials in a single process step. However, development of this technique has been limited by a lack of fundamental computational modeling, which is necessary for both multiscale modeling and targeted experimental efforts. Previously, our team has used Blue Waters to simulate ion bombardment of a large-cell GaSb surface (100×100×10 nm³) using molecular dynamics for ion fluences up to ~10¹⁴ ions/cm² (~10⁴ consecutive impacts). These simulations have shown evidence of athermal, irradiation-induced Gibbsian phase segregation on pattern-relevant length scales, indicating the probable driving mechanism for quantum dot formation on the surfaces of irradiated III-V semiconductors. In this proposal, we expand the previous work to cover higher irradiation fluences (up to 10¹⁵ cm^-2) as well as multiple different incident ion species (Ne⁺, Ar⁺, and Kr⁺ incident at 500 eV) with the intention of functionalizing the irradiation-induced mechanisms and surface evolution with respect to these relevant experimental parameters. This project will only be possible through the use of highly-parallel petascale computing power available in the form of Blue Waters, as the scale of the simulation would require decades to run on a smaller system. This work will ultimately lay a foundation for building up scalable manufacturing techniques for advanced nanomaterials to be used in areas as diverse as biomaterials, semiconductor fabrication, or energy applications.