Phase diagram of the face-centred cubic Blume–Emery–Griffiths model in the cluster variation method tetrahedron approximation

1993 ◽  
Vol 14 (4) ◽  
pp. 1209-1215 ◽  
Author(s):  
C. Buzano ◽  
L. R. Evangelista
Keyword(s):  
Phase Diagram ◽  
Cluster Variation Method ◽  
Variation Method ◽  
The Face ◽  
Cluster Variation

THREE- AND FOUR-BODY CORRELATION FUNCTIONS FOR THE BLUME-CAPEL MODEL

1993 ◽  
Vol 07 (05) ◽  
pp. 1259-1274 ◽  
Author(s):  
C. BUZANO ◽  
L.R. EVANGELISTA
Keyword(s):  
Correlation Functions ◽  
Tricritical Point ◽  
Cluster Variation Method ◽  
Variation Method ◽  
Face Centered Cubic ◽  
The Face ◽  
Cluster Variation ◽  
Face Centered ◽  
Recent Formulation ◽  
Body Correlation

The Cluster Variation Method (CVM), in its recent formulation using the Moebius Inversion, is applied to study the critical properties of the face-centered-cubic Blume-Capel model in the triangle and tetrahedron approximations. We develop a procedure which preserves the characteristics of Kikuchi’s Natural Iteration Method, moreover reducing considerably the number of involved variables. The resulting phase diagram is compared with that obtained from lower orders of CVM approximation (single-site and pair) and from other methods (series expansions, Monte Carlo, …). The tetrahedron approximation shows a good agreement with these high-precision methods, in particular for the location of the tricritical point. The behavior of order parameters and multisite (up to four-body) correlation functions is determined for all significant regions of the phase space.

Glass Transition within the Cluster Variation Approximation

2007 ◽  
Vol 26-28 ◽  
pp. 723-726
Author(s):  
Tetsuo Mohri
Keyword(s):  
Phase Diagram ◽  
Free Energy ◽  
Glass Transition ◽  
Cluster Variation Method ◽  
Variation Method ◽  
Cluster Variation ◽  
Ordering Transition ◽  
Limiting Case ◽  
The Ideal

The detailed behavior of the free energy of Cluster Variation Method in the vicinity of spinodal ordering transition is examined. The generalized phase diagram proposed in the previous study is modified and spinodal ordering transition is reinterpreted as a limiting case of the ideal glass transition.

Phase Diagram of Ni-Pt from Linear Muffin-Tin Orbitals Total Energy Calculations

1991 ◽  
Vol 253 ◽  
Author(s):  
C. Amador ◽  
W. R. L. Lambrecht ◽  
B. Segall
Keyword(s):  
Phase Diagram ◽  
Effective Interaction ◽  
Cluster Variation Method ◽  
Variation Method ◽  
Ordered Structures ◽  
Atomic Sphere ◽  
Sphere Approximation ◽  
Total Energies ◽  
The Difference ◽  
Cluster Variation

ABSTRACTProgress in the calculation of the phase diagram of the Ni-Pt compounds from "first-principles" is reported. Our procedure consists of: (1) calculating total energies for ordered structures as a function of volume and including internal relaxations by means of the linear muffin-tin orbitals method within the atomic sphere approximation; (2) mapping these results onto an Ising model with effective interaction parameters; and (3) calculating the phase diagram by means of the cluster variation method. We identify the elastic energy related to the difference in the Ni and Pt lattice constant as one of the major problems in this system and discuss the convergence of the cluster expansion of the energy.

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