Correlations and Ordering in (GaSb)1−xGe2x Alloys

1986 ◽  
Vol 77 ◽  
Author(s):  
Kathie E. Newman ◽  
Bing-Lin Gu ◽  
P. A. Fedders
Keyword(s):  
Phase Transition ◽  
Bond Length ◽  
Long Range ◽  
Short Range ◽  
Short Range Order ◽  
Range Order ◽  
Exafs Data ◽  
Disorder Transition ◽  
Vegard’S Law ◽  
The Mean

ABSTRACTThe semiconducting alloy (GaSb)1−x Ge2x is an example of a mixed crystalline alloy that undergoes a phase transition between its constituent crystal types. The order-disorder transition modifies both the long-range and short-range order in the alloy as a function of composition x. By using the Kikuchi approximation, the bond probabilities are calculated and then compared with EXAFS data. These calculations show that the EXAFS data are consistent with the existence in (GaSb)1−x Ge2x of “wrong” bonds of Ga-Ga and Sb-Sb. The theory also predicts a violation of Vegard's Law for the behavior of the mean bond length as a function of composition x.

LONG RANGE 1-d POTENTIAL AT BORDER OF THERMODYNAMIC LIMIT

2006 ◽  
Vol 20 (11) ◽  
pp. 649-654 ◽  
Author(s):  
O. SHANKER
Keyword(s):  
Phase Transition ◽  
Long Range ◽  
Thermodynamic Limit ◽  
Short Range ◽  
Short Range Order ◽  
Range Order ◽  
Long Range Order ◽  
Important Conclusion ◽  
Great Caution ◽  
Sufficiency Conditions

In this work we consider new forms of the 1-d long range potential close to the thermodynamic limit. We also look at the potential close to the transition from long range order to short range order. We find an interesting duality between the two potentials, based on Dyson's sufficiency conditions for the existence of a phase transition. An important conclusion of our study is that the very long range nature of the potential causes Monte Carlo simulations to reach an apparent, but misleading, convergence. Thus, one needs to exercise great caution in deriving conclusions from such studies.

Long-Range Order and Short-Range Order inPd3V: Breakdown of the Mean-Field Theory

1987 ◽  
Vol 58 (21) ◽  
pp. 2245-2248 ◽  
Author(s):  
F. Solal ◽  
R. Caudron ◽  
F. Ducastelle ◽  
A. Finel ◽  
A. Loiseau
Keyword(s):  
Field Theory ◽  
Long Range ◽  
Short Range ◽  
Short Range Order ◽  
Mean Field Theory ◽  
Mean Field ◽  
Range Order ◽  
Long Range Order ◽  
The Mean

Pb()O3-type Perovskites: Part I. Pair-correlation Theory of Order-disorder Phase Transition

1997 ◽  
Vol 12 (8) ◽  
pp. 2117-2126 ◽  
Author(s):  
Hyun M. Jang ◽  
Su-Chan Kim
Keyword(s):  
Long Range ◽  
Order Parameter ◽  
Short Range ◽  
Short Range Order ◽  
Pair Correlation ◽  
Range Order ◽  
Statistical Thermodynamic ◽  
Range Order Parameter ◽  
Long Range Order ◽  
Short Range Order Parameter

The limitation of the long-range order parameter and the necessity of the short-range order parameter for the thermodynamic description of Pb()O3-type perovskites are discussed. Based on the discussion, a statistical thermodynamic model that takes into account the configuration of the neighboring B-site ions (B′ and B″ cations) was developed. A pair-correlation approximation was used in the calculation of the configurational entropy and the long-range coulombic interaction energy between the nearest B-site ions. The theoretical calculations using Pb(Sc1/2Ta1/2)O3 (PST) and Pb(Sc1/2Nb1/2)O3 (PSN) systems indicate that the short-range order parameter persists over a wide range of temperatures examined (0–1800 K) and that there possibly occur consecutive long-range order-disorder transitions in the configuration of B-site cations. The possibility of the existence of short-range ordering above the long-range order-disorder transition temperature was also examined using the annealed PSN specimen as a typical example of Pb()O3-type perovskites.

On `non-stoichiometric phases' in thin films of rare-earth oxides

1978 ◽  
Vol 34 (6) ◽  
pp. 1025-1027 ◽  
Author(s):  
M. Gasgnier ◽  
P. Caro
Keyword(s):  
Thin Films ◽  
Rare Earth ◽  
Long Range ◽  
Short Range ◽  
Short Range Order ◽  
Rare Earth Oxides ◽  
Range Order ◽  
Acta Cryst ◽  
The Rare Earth

Kaul & Saxena [Acta Cryst. (1977), A33, 992-996] have reported the existence of long-range and short-range order in a non-stoichiometric phase 'LnO x ' (Ln = rare earth). It is shown that the experiments they are describing are indeed the oxidation of the rare-earth hydride LnH2 into the rare-earth cubic C-type sesquioxide. The interpretation they give of their experiments is to be discarded entirely.

Short range order and its transformation to long range order in Ni4Mo

1998 ◽  
Vol 46 (3) ◽  
pp. 881-892 ◽  
Author(s):  
Satoshi Hata ◽  
Syo Matsumura ◽  
Noriyuki Kuwano ◽  
Kensuke Oki
Keyword(s):  
Long Range ◽  
Short Range ◽  
Short Range Order ◽  
Range Order ◽  
Long Range Order
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