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Anders Mikkelsen. Portrait.

Anders Mikkelsen

Professor

Anders Mikkelsen. Portrait.

Density of configurational states from first-principles calculations: The phase diagram of Al-Na surface alloys

Author

  • Mikael Borg
  • C Stampfl
  • Anders Mikkelsen
  • Johan Gustafson
  • Edvin Lundgren
  • M Scheffler
  • Jesper N Andersen

Summary, in English

The structural phases of AlxNa1-x surface alloys have been investigated theoretically and experimentally. We describe the system using a lattice gas Hamiltonian, determined from density functional theory together with Monte Carlo (MC) calculations. The obtained phase diagram reproduces the experiment on a quantitative level. From calculation of the (configurational) density of states by recently introduced Wang-Landau MC algorithm, we derive thermodynamic quantities such as free energy and entropy which are not directly accessible from conventional MC simulations. We accurately reproduce the stoichiometry, as well as the temperature at which an order-disorder phase transition occurs, and demonstrate the crucial role, and magnitude of the configurational entropy.

Department/s

  • Synchrotron Radiation Research

Publishing year

2005

Language

English

Pages

1923-1928

Publication/Series

ChemPhysChem

Volume

6

Issue

9

Document type

Journal article

Publisher

John Wiley & Sons Inc.

Topic

  • Atom and Molecular Physics and Optics

Keywords

  • phase
  • phase diagrams
  • alloys
  • density functional calculations
  • surface chemistry
  • transitions

Status

Published

ISBN/ISSN/Other

  • ISSN: 1439-7641