First-principles calculations of quartz-coesite interfaces.

Abstract

Atomistic interface structures compatible with periodic boundary conditions for the strain-induced subsolidus martensitic transition between quartz and coesite have been investigated. We identified layers of atoms that remained unchanged in terms of neighbor interactions throughout the transformation. Our analysis revealed that the orientation relationships between quartz and coesite, namely (1011)_Qz||(010)_Coe and (1321)_Qz||(010)_Coe, are consistent with experimental observations. Using density-functional-theory-based tight-binding model cal-culations, we determined an interface energy of approximately 660 mJ m^-2 for these interfaces and strain energies of 196 (6) and 2760 (160) J mol^-1 atom^-1 for the (1321)_Qz||(010)_Coe and (1011)_Qz||(010)_Coe oriented interfaces, respectively. To visualize these interface structures and facilitate their identification in experiments, we simulated high-resolution transmission electron microscopy images and electron diffraction patterns.