Thermodynamic Behavior of Nano-sized Gold Clusters on the (001) Surface

Abstract

We have studied thermal expansion of the surface layers of the hexagonally reconstructed gold (001) surface using a classical Molecular Dynamics (MD) simulation technique with an Embedded Atomic Method (EAM) type many-body potential. We find that the top-most hexagonal layer contracts as temperature increases, whereas the second layer expands or contracts depending on the system size. The magnitude of expansion coefficient of the top layer is much larger than that of the other layers. The calculated thermal expansion coefficients of the top-most layer are about -4.93 10(-5)A/K for the ( 262 x 227 ) cluster and -3.05 10(-5) A/K for (101 x 87) A cluster. The Fast Fourier Transform (FFT) image of the atomic density shows that there exists a rotated domain of the top-most hexagonal cluster with rotation angle close to 1 at temperature T < 1000K. As the temperature increases this domain undergoes a surface orientational phase transition. These predictions are in good agreement with previous phenomenological theories and experimental studies.

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Document Details

Document Type
Technical Report
Publication Date
Jun 01, 2001
Accession Number
ADA392625

Entities

People

  • Min Namkung
  • Russell A. Wincheski
  • Sun M. Paik
  • Sung M. Yoo

Tags

Communities of Interest

  • Advanced Electronics

DTIC Thesaurus Topics

  • Abstracts
  • Atoms
  • Boundaries
  • Coefficients
  • Computer Science
  • Contracts
  • Fast Fourier Transforms
  • High Temperature
  • Molecular Dynamics
  • Phase
  • Phase Transformations
  • Rotation
  • Simulations
  • Symmetry
  • Thermal Expansion
  • Transitions
  • Virginia

Fields of Study

  • Physics

Readers

  • Fluid Mechanics and Fluid Dynamics.
  • Materials Science and Engineering.
  • Quantum Chemistry