Surface strain tensor elastic deformation

The second contribution to the surface energy is new because it is based on an extension of the atomic distances in the surface area by a force called surface stress. The symbol used for the surface stress in this book is T as in the review of Linford. The surface stress is a tensor with the tensor components T, T, T, and T. The tensor is only independent in its direction for an isotropic sohd. The surface stress causes an elastic deformation of the surface described by the surface strain tensor e. ... 

Surface stress — The surface area A of a solid electrode can be varied in two ways In a plastic deformation, such as cleavage, the number of surface atoms is changed, while in an elastic deformation, such as stretching, the number of surface atoms is constant. Therefore, the differential dUs of the internal surface energy, at constant entropy and composition, is given by dUs = ydAp + A m g m denm, where y is the interfacial tension, dAp is the change in area due to a plastic deformation, gnm is the surface stress, and enm the surface strain caused by an elastic deformation. Surface stress and strain are tensors, and the indices denote the directions of space. From this follows the generalized Lippmann equation for a solid electrode ... 

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