STUDY OF BULK AND NANOSCALE
MATERIALS BY TIGHT-BINDING
AND PATH PROBABILITY METHODS
K. Masuda-Jindoa, R. Kikuchib, and
M. Menonc

UDC 531.4:541.1:519.21

The generalized tight-binding molecular dynamics (TBMD) 
method is used to study the atomistic and mechanical properties of 
the nanoscale materials and the calculated properties are compared 
with those of the corresponding bulk materials. We report that the 
thermodynamic and mechanical properties of the nanoscale materials 
are quite different from those of the corresponding bulk materials. 
For instance, it has been found that the excess energies of dislocations 
in the small crystallites are very small and often take negative values 
due to the atomistic "image effects". The edge dislocation in the 
carbon nanotubes, whose core is characterized by a pentagon-heptagon 
pair is found to act as a center of the stress concentration and contribute 
to the peculiar nanoplasticity in the quasi-one-dimensional (1D) cylindrical 
structures. Using the path probability method (PPM) in the statistical 
physics, we also study the growth and microstructure of strained SiGe 
deposited films on Si(001) substrate, taking into account the composition 
gradient and influence of the strain filed at the heterojunction.

aDepartment of Materials Science and Engineering, 
Tokyo Institute of Technology, Nagatsuta, Midori-ku, Yokohama 226-8503, 
Japan; email: kmjindo@issp.u-tokyo.ac.jp;
bMaterials Science and Mineral Engineering, University of California, 
Berkeley, CA 94720-1760, USA; 
cDepartment of Physics and Astronomy, University of Kentucky, 
Lexington, Kentucky 40506, USA. 
Original article submitted December 19, 2000.

JEPTER7492020011
JEPTER749201