Short-range order in Ising-like models with many-body interactions: Description via effective pair interactions

Journal Article · Fri Sep 01 00:00:00 EDT 1989 · Physical Review (Section) B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.40.4990· OSTI ID:5551883

Schweika, W ^[1]; Carlsson, A E ^[2]

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1. Institut fur Festkorperforschung der Kernforschungsanlage Julich, D-5170 Julich, Federal Republic of Germany (DE)
2. Department of Physics, Washington University, St. Louis, Missouri 63130

The validity of approximating the effects of many-body interactions in Ising-type models by several types of pair interactions is examined. In addition to the bare pair interaction ({ital P}{sub 0}), two interactions derived via high-temperature approximations are considered. The first ({ital P}{sub 1}) is concentration dependent and is obtained by an expansion to first order in inverse temperature; the second ({ital P}{sub 2}), obtained by a second-order expansion, is both temperature and concentration dependent. The validity of the pair approximations is evaluated by Monte Carlo calculations of ordering and thermodynamic properties for a particular many-body interaction model on a fcc lattice. In the high-temperature limit, the structure (as described by pair and multiple correlation functions) is accurately obtained by both the interactions {ital P}{sub 1} and {ital P}{sub 2}, but not by {ital P}{sub 0}. Over a much wider range of temperatures, {ital P}{sub 2} still yields accurate results. However, none of the pair interaction models obtain accurate mixing enthalpies. The connections that are derived between the strength of the many-body interactions, and the environmental dependence of the effective pair interactions, provide a possible way of evaluating the importance of the many-body interactions in solid solutions from diffuse scattering measurements.

• OSTI ID: 5551883
• Journal Information: Physical Review (Section) B: Condensed Matter; (USA), Vol. 40:7; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ISING MODEL
MANY-BODY PROBLEM
MONTE CARLO METHOD
ORDER-DISORDER TRANSFORMATIONS
PAIRING INTERACTIONS
QUANTITY RATIO
SERIES EXPANSION
TEMPERATURE DEPENDENCE
THERMODYNAMIC PROPERTIES
CRYSTAL MODELS
INTERACTIONS
MATHEMATICAL MODELS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
656002* - Condensed Matter Physics- General Techniques in Condensed Matter- (1987-)