Allen group Computational Nanoscience


Two computational areas of nanoscience are currently active: (1) molecular electronics, and (2) nanowires.

Molecular electronics

Yulia Gilman's PhD research involves electrical conductance of nanoscale systems, and the chemistry of molecular attachment to metal surfaces.  Below is shown a schematic diagram of CH3NC (methyl isocyanide) on a gold (111) surface.  The terminal carbon prefers to attach on top of a gold atom, much like the way the CO molecule attaches to gold.  This system has been studied using density functional theory (DFT).  Our work is in collaboration with Mark Hybertsen at Brookhaven National Lab. 

Yulia Gilman, Philip B. Allen, and Mark S. Hybertsen,
"Density-Functional Study of Adsorption of Isocyanides on the Gold (111) Surface,”
cond-mat/0411320


methyl isocyanide on gold (111)


Theory of nanowires


Xiao Shen's PhD research is a study of nanowire properties using density functional theory.  Below is shown some wavefunctions on a cross-section of a ZnO nanowire.  Our collaborators are Mark Pederson of NRL, and Jincheng Zheng, Jim Davenport, and Jim Muckerman, of BNL.

Xiao Shen, Mark R. Pederson, Jin-Cheng Zheng, James W. Davenport, James T. Muckerman, and Philip B. Allen
"Electronic Structure of ZnO nanowire,”
cond-mat/0610002.


 
ZnO HOMO level wavefunction a
 ZnO nanowire HOMO level b
 ZnO nanwire LUMO level (m=0)

Other papers on nanoscience


Philip B. Allen,
"Dipole Interactions and Electrical Polarity in Nanosystems -- the Clausius-Mossotti and Related Models"
cond-mat/0307209; J. Chem. Phys. 120, 2951-2962 (2004).

Philip B. Allen
"Dipole Interactions in Nanosystems"
cond-mat/0309392; in Molecular Nanowires and Other Quantum Objects,
edited by A. S. Alexandrov, J. Demsar, and I. K. Yanson
(NATO Science Series, II. Mathematics, Physics, and Chemistry – Vol. 148)
(Kluwer, Dordrecht, 2004) pp. 29-38.

A. V. Shytov and P. B. Allen,
"Electronic Polarity of Nanoclusters: Quantum and Many-Body Effects,"
cond-mat/0509124 Phys. Rev. B 74, 075419:1-6 (2006).

Philip B. Allen,
"Nanocrystalline Nanowires I: Structure"

Philip B. Allen,
"Nanocrystalline Nanowires II: Phonons"

Philip B. Allen,
"Nanocrystalline Nanowires III: Electrons"