Strain energy between parallel {001} crystallographic shear planes in the tungsten trioxide structure

Abstract

In order to clarify the appropriateness of the proposal of Iguchi and Tilley, in which the force between two parallel crystallographic shear ( CS) planes at low separations is an attractive one and, at high separations, a repulsive one, the strain energy between {001} CS planes was calculated as a function of the separation. The strain energy was presumed to be due to the forces acting on cations in the CS planes and was calculated by using classical elasticity theory by way of the elastic Green's function. The result obtained is in agreement with the original proposal but the CS plane separation at which the force between them changes from an attractive to a repulsive one is much larger than was estimated previously. The strain-energy curve has, in addition, a plateau where the interaction of the paired CS planes is likely to be in the metastable state. The difference between other related results and ours is discussed in terms of the difference of the model employed.