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oai:www.ideals.illinois.edu:2142/83908 2023-07-11 col_2142_5131 col_2142_14787 com_2142_5130 com_2142_9630 com_2142_234

Aluru, Narayana R. Tang, Zhi 2015-09-25T21:12:41Z 2015-09-25T21:12:41Z 10000-01-01 2008 2008 Next, we extend the quasicontinuum (QC) approach for multiscale analysis of silicon nanostructures at finite temperature. Three models, namely the real space quasiharmonic (QHM) model, the local quasiharmonic (LQHM) model, and the reciprocal space quasiharmonic (QHMK) model are investigated. Within this framework, we compute the effect of the temperature and strain on mechanical properties of silicon. We also compute the mechanical response of silicon nanostructures for various external loads. Furthermore, a more efficient multiscale model is presented for mechanical analysis of nanostructures at finite temperature, by combining the QHMK and LQHM models. Finally, we investigate thermodynamic and mechanical properties of silicon nanostructures at finite temperature by using a QHMG approach - where the quasiharmonic approximation is combined with the local phonon density of states (LPDOS). The LPDOS is efficiently calculated from the phonon Green's function by using a recursion technique. Considering different surfaces of a silicon nanowire, we calculate the local thermodynamic properties at finite temperature and observe that the surface effects on the local thermal and mechanical properties are localized to within one or two atomic layers of the nanowire. Made available in DSpace on 2015-09-25T21:12:41Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 3314913.pdf: 1982332 bytes, checksum: 964ea86e61faa560e69bfe16f1c92412 (MD5) Previous issue date: 2008 Embargo set by: Seth Robbins for item 85189 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs U of I Only 132 p. Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2008. http://hdl.handle.net/2142/83908 (MiAaPQ)AAI3314913 eng Physics, Atomic Computational Analysis of Silicon Nanoelectromechanical Systems text Mechanical Engineering Mechanical Engineering University of Illinois at Urbana-Champaign Dissertation Ph.D.