Finite-size scaling study of a lattice-gas model for oxygen chemisorbed on tungsten

Tutkimustuotos: Lehtiartikkelivertaisarvioitu

Tutkijat

Organisaatiot

  • Stony Brook University
  • Temple University
  • Tampere University of Technology
  • Middle East Technical University

Kuvaus

We present a finite-size scaling study of a centered rectangular lattice-gas model with attractive nearest-neighbor interactions and repulsive second- and third-neighbor and three-particle interactions, as well as attractive fifth-neighbor interactions. This has been proposed as a model for atomic oxygen adsorbed on a (110) surface of tungsten. The ordered phases are a (2×1) phase with coverage 12 and a (2×2) phase with coverage 34. We obtain phase diagrams which are in good qualitative agreement with the available experimental information. This agreement is obtained with considerably weaker attractive fifth-neighbor interactions than previously suggested by ground-state and Monte Carlo calculations, but consistent with the results of quantum-mechanical band calculations. In particular, we find a multicritical point below which the low-coverage (2×1)-to-disorder transition is of first order. We also find indications of a previously undetected low-temperature multicritical point below which the high-coverage (2×2)-to-disorder transition may be of first order. The finite-size effects in this study are considerably stronger than in previous studies of simpler lattice-gas models. This limits the accuracy with which we can determine the multicritical temperatures. It also prevents us from obtaining reliable estimates of the nonuniversal critical exponents for this model.

Yksityiskohdat

AlkuperäiskieliEnglanti
Sivut6285-6294
Sivumäärä10
JulkaisuPhysical Review B
Vuosikerta29
Numero11
TilaJulkaistu - 1984
OKM-julkaisutyyppiA1 Julkaistu artikkeli, soviteltu

ID: 9953970