Notices to the applications of Miedema’s model

It is pleased that some people would like to use Miedema’s model to calculate the formation enthalpy. However, notices must be announced to avoid the misunderstanding of Miedema’s theory. For example, some researchers may make the following mistakes when applying the Miedema’s model

1) “the proposed extension to Miedema’s model lacks symmetry for the interchange of metals, whereas Miedema’s model does.” [M1] This is an incorrect understanding to Miedema’s theory because, such the symmetry is also not shown in the original Miedema’s model, and the asymmetry is an important physical feature of Miedema’s model [M2]. Please refer to the following comparison,

2) If one didn’t notice the absolute (“| |”) symbol in the Eq. (2) below, one may get problem which is simply due to the incorrect application of the formulae (1) and (2) [M1] [M2]. The clarification is given below for your attention: 

3) In addition, to be noticed is the composition dependence must be kept in mind, i.e. the solute concerntration must be used to avoid confusing, and accordingly  must be the solute related quantity.

4) Notice that the proposed atomic size difference factor S(c) in [M2][M3] should be corrected as (i.e. using mole concentration cA or cB to replace surface concentration of csA and csB) to get consistent values. Surface concentrations are used for the calculation of f(c) factor. However, atomic size difference factor may be adopted in different forms to improve the statistical agreement with experimental values. In such case the surface concentration may be used for comparison.

Correction1More clarification can be found in Ref. [M1][M2] [M3] 

[M1] X.Q. Chen, R. Podloucky, P. Rogl, and W. Wolf, Appl. Phys. Lett. 86 (2005) 216103.

[M2] R.F. Zhang, B.X. Liu, Applied Physics Letters 86/21 (2005) 216104.

[M3] R.F. Zhang, S. H. Sheng, and B.X. Liu, Chem. Phys. Lett. 442 (2007) 511–514