Mixing of phases in non-crystalline materials: Application to carbon

Abstract

The atomic structure of non-crystalline solids is described by the correlation function. When more than one phase is present, the simple addition of the correlation functions for the various phases in proportion to their concentrations within the system is not valid, except in the case of the completely phase-separated system. The overall correlation function must reflect the boundaries between the various phases within the system. The cross correlation functions between the phases have a dependence both on the degree of mixing of the phases and also on the sizes of the domains of the phases. The correlation function for a non-crystalline solid with more than one phase has been derived in a general way. Particular application has been made to non-crystalline carbon for which the correlation function given previously did not have the correct limits because of absence of the cross correlation terms.