Defect thermodynamics of the interface

Before we turn to the examples, we have to discuss briefly how the interface chemistry can be related to the parameter cq, i.e. to t (cf. Section 5.4.3). Let us consider. 

1) The first step involves solution of the bulk problem, i.e. relating ccy oo and Ch oo to the material parameters and the control parameters, temp erature, component activity and doping content. In view of the treatment already given we can regard this problem as having been solved (see Eq. (5.150)). 

3) For this purpose we consider the transfer of the two defects from position x=0 to the neighbouring, but structurally different, layer x=s (Fig. 5.80), where the countercharge is situated, that is to the actual surface  

These two processes are associated with a change in both the standard chemical potentials and the electrical potential (electrochemical process E ). It is also necessary to use the activity a, at least for x = s  

The electrostatic contributions are the same for ionic and electronic defects apart from the charge numbers, while the chemical contributions naturally differ. The parameters /Xq and depend on the bulk mass action constants of the reaction O (see Eq. (5.129))  

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