Dynamical behaviour and size dependence of 2D copper islands on the Cu(111) surface: a molecular dynamics study
Loading...
Date
Authors
Vamvakopoulos, E.
Evangelakis, G. A.
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Type
Type of the conference item
Journal type
peer reviewed
Educational material type
Conference Name
Journal name
Journal of Physics-Condensed Matter
Book name
Book series
Book edition
Alternative title / Subtitle
Description
Using molecular dynamics simulations based on an effective potential, in analogy to the tight binding theory in the second-moment approximation, we studied the vibrational behaviour of Cu islands of various sizes on the Cu(111) surface. We found that small clusters are contracted by as much 10% (for a dimer) from the relative positions of the relaxed interlayers of the island's atoms; the effect is less important with increasing cluster size, N, attaining the same value as for the surface atoms for islands with more than Nc = 33 atoms. In addition, from the calculated mean-square displacements, we found that in the direction normal to the surface the vibrational amplitudes of the island's atoms do not depend on the size of the cluster, while they are increased by a factor of five in the in-plane directions. These findings are compatible with the behaviour of the cluster phonon modes. Indeed, we found that small islands introduce new vibrational modes that diminish with increasing cluster size, regaining the surface vibrational behaviour. These results suggest that small 2D islands (containing up to 10 atoms) formed on the Cu(111) face are strained; for larger islands this compressive stress is released and the islands exhibit the vibrational behaviour of the substrate for N > Nc. This characteristic cluster size, Nc, coincides with the characteristic island size above which the migration energy of the island's atoms saturates to the value of the step-energy barrier.
Description
Keywords
adatom self-diffusion, layer growth, clusters, cu, face, temperature, simulation, vibrations, energetics, energies
Subject classification
Citation
Link
<Go to ISI>://000172943600008
http://iopscience.iop.org/0953-8984/13/48/302/pdf/0953-8984_13_48_302.pdf
http://iopscience.iop.org/0953-8984/13/48/302/pdf/0953-8984_13_48_302.pdf
Language
en
Publishing department/division
Advisor name
Examining committee
General Description / Additional Comments
Institution and School/Department of submitter
Πανεπιστήμιο Ιωαννίνων. Σχολή Επιστημών και Τεχνολογιών. Τμήμα Βιολογικών Εφαρμογών και Τεχνολογιών