Manipulating the Toughness of Rocks through Electric Potentials, Year 2

When rocks are stressed, electronic charge carriers are activated which are defect electrons in the oxygen anion sublattice, O? in a matrix of O2?, known as positive holes. They have properties such as the ability to flow out of the stressed volume and spread into the surrounding unstressed rocks. The wave function associated with these charge carriers is highly delocalized, meaning that the spin density is distributed over hundreds of O2? neighbors.